LIBRARY OF CONGRESS, 



COPYRIGHT OFFICE. 



No registration s*#*fc of this book 
as a preliminary to copyright protec- 
tion has been found. 

JUN 15 1910 

Forwarded to Order Division 



(Date) 



(Apr. 5, 1901—5,000. 



&0 




Class. 
Book 



-/ 




Fig. 77. 

A passion flower. Photographed by the late Dr. J. R. Weist. 



NATURE STUDY 



ONE HUNDRED LESSONS ABOUT 
PLANTS 



BY 



DAVID WORTH DENNIS, 

Professor of Biology in Earlham College. 



With More Than One Hundred and Fifty Illustrations. 



Marion, Indiana. 

Teachers Journal Printing Co., 

1906. 






Copyright, 1903, 

BY 

O. W. FORD & CO. 



., 4 front* 

Copyright Office. 

JUN 16 1910 



^ 



This Book is Dedicated to all who Are Helped by it. 



PREFACE 

Nature Study is new ; Liebig was the first man who used a labora- 
tory for instruction. He began his career as a teacher in 1824. 

Courses in mathematics and language have had centuries in 
which to perfect their methods of instruction and the lessons it is 
best to offer; for this reason, lessons in these subjects are good, 
if not the best, that can be offered, and the methods of giving 
them have had opportunity to eliminate errors. The teacher of 
nature study has almost no past to guide him. The older teachers 
of nature study were not themselves taught in schools. As a 
department of instruction it is without traditions or precedents. 
Every serious teacher so far has had to pave his own road. All 
teachers have gone different roads. It could not be otherwise. 

The material with which nature study deals, is inexhaustible; no 
one can ever be acquainted with more than an insignificant frac- 
tion of it. It is all good. It will always be the case that success- 
ful teachers will give what they know. They will accordingly 
teach different things. It is probably true that every successful 
teacher has, from year to year, taken his pupils over different 
ground, and that everything done has proved to be good. What it 
is best to teach we cannot yet tell, in other words, than that that 
material is best -which can be had. 

This nature study work has passed through three phases. It 
was first taught from books. The only nature study work I ever 
did in school was in Geography and Physiology and every syllable 
of these came from books. We next added the laboratory. How 
new this phase of the subject is, may be learned from the presi- 
dential address of Dr. Wiley before the Indiana Science Teachers' 
Association at Lafayette, in 1895. He says: "Prior to 1863 no 
laboratory instruction was given in Indiana except a little in 
qualitative analysis." 

Much has come from the laboratory as a means of instruction. 
But we had not been trying it long when we learned that though 
the laboratory, like the book, is a great help, still it is not enough. 
Aristotle had set us our task; Zoology has its end not in what an 
animal is or what it does, but why it does it. Fitness is the real 
Zoology. We had studied the sucker in books and learned much; 



vi Preface. 

we brought him to the laboratory and learned more, but the sucker 
had spots. Why did he grow them? We had to go to the brook 
for answer; his spots resemble the stones on the bottom of the 
stream. He grew them in imitation of this bottom, and he thus 
often escaped his enemies. This brought us to the third phase, 
the outing. This is now in full swing; nature study of whatever 
degree cannot do without it. The Gulf Stream and the Rocky 
Mountains we cannot take to the school, but we can and do take 
the school to them. 

It is now known that nothing we ever did was wholly wrong. 
The book, the laboratory, the outing, all were necessary. This 
book emphasizes the outing, but contemplates the use of book and 
laboratory as well. 

The outing, to be successful, must have a definite purpose and 
nearly all the lessons and exercises here given hold up one thing 
to be learned. 

This one thing should be important. The teacher and pupil 
alike should be able to see that the lesson is worth while. Terns 
incidentally necessary to the learning o± the lesson should be 
acquired by use first. Let definitions wait until they are needed. 
The excuseless thing that nature study has done is: it has piled 
up definitions of parts, forms, disguises, etc., by the hundreds 
of pages and has turned them on in installments, away from what 
they represent and apart from any possible use that the learner 
could see. This book has been written with the conviction that 
this ought to stop. If it has left undefined any necessary terms 
for any lesson, Webster, Worcester or the Century at least, will 
supply the omission. 

It has been the constant aim of these pages to put the student in 
possession of guiding principles,— something that will help him 
interpret what he sees. Nearly all the lessons consider, in one 
form or another, the plant in question as a species that has won 
in the struggle for existence and they direct attention to the adap- 
tations that have enabled it to win. 

It is my conviction that knowledge on the part of the teacher 
is the chief thing we lack. This consideration has led me to con- 
fine these lessons to a field so limited that it would be possible for 
the faithful teacher to gain the necessary knowledge. I do not 
see how I could, give these lessons without knowing the plants in 
question by name. This is the first thing children ask and the 
best way to induce them to learn the important things the teacher 
assigns is for him to tell them the unimportant (?) things they 



Preface. vii 

ask. These lessons mainly deal with common trees; but a teacher 
should have a good manual of botany and know how to use it to 
find the name of a plant. For the Ohio Valley, Gray's Manual 
is a good one for determining the names of flowering plants. Ap- 
gar's Trees of the Northern United States will enable any teacher 
to find the name of most, if not all, trees by their leaves only. 
A good general botany is Campbell's University Botany. Three 
good smaller works are Bailey's Elementary Botany, Coulter's 
Plant Relations and Plant Structures, and Atkinson's Elementary 
Botany. The catalogue prices of these books and their publishers, 
are as follows: 

Bailey's Elementary Botany, The Macmillan Co., SI. 10. 
Coulter's Plant Relations, $1.10; Coulter's Plant Structures, SI. 20, D. Appleton 
& Co. 

Atkinson's Elementary Botany, Henry Holt & Co., $1.25. 

Campbell's University Botany, The Macmillan Co., $4.00. 

Apgar's Trees, The American Book Co., $1.00. 

Gray's Manual, The American Book Co., $1.65. 

A summer term in some lakeside or seaside laboratory, would be 
of the greatest value to any prospective teacher of nature study. 
It may be depended upon that in science, with fullness of knowl- 
edge, enthusiasm and some good way to teach, will follow. 

There is another sort of literature that the teacher should use 
for the sake of the pupil: Stories and poems by masters that treat 
directly or indirectly of plants. Only selections should be used 
that are worthy; that belong to enduring literature. The follow- 
ing list will show the character of the reading to which I refer: 

Bryant, "The Yellow Violet," "The Fringed Gentian," "The Death of the 
Flowers;" Wordsworth, "The Oak and the Broom," "Daffodils" — "I wandered 
lonely as a cloud," "To the Celandine;" Emerson, "The Rhodora;" Burns, "To 
a Mountain Daisy;" Dickens, "The Ivy Green;" Holmes, "Album Verses;" Southey, 
"The Holy Tree;" Santine, "Picciola;" Thoreau, "The Succession of Forest Trees;" 
Kipling, "The Jungle Books." 

In addition to these there are hundreds of other worthy refer- 
ences to plants in the works of all our standard authors, from 
Shakespeare to Riley. Hunt them up and they are yours. 

NATURE STUDY AND THE CHILD. 

My last recommendation may be criticised or called sentiment 
or anything else, so the critic remembers it concerns itself with the 
child's need; his nature; his demands; the child's imagination is 
fairly riotous and must be directed; because poetry and story 



viii Preface. 

were the first phases of the world's literary activity, they appeal 
to the mind of the growing child. Let him have them, part of the 
time, and let them wed him to his more serious nature study as 
they are sure to do. It is maintained that the imagination is to 
be cultivated, but not in connection with nature study. But sup- 
pose history teachers fence their preserve the same way? and 
teachers of religion and sociology? 

It has been said that this child preference for poetry, story, 
myth and the heroic, is a "passing phase;" the tadpole's tail is a 
"passing phase" but the stronger you make it the further the 
frog will be able to jump. Let the child enjoy nature study, 
science can stand it in any event and will gain by it if it helps the 
child. As his interest in the subject grows, his need of any fanciful 
presentation will decline. 



The child's powers of observation are proverbial; his desire for 
knowledge is keen; it is universal among normal children; his 
curiosity leads him to ask questions; disapproval or even punish- 
ment will not stop his questioning. He only leaves it off when he 
despairs of an answer. His impossible questions mean only that 
his mind is awake and hungry; show him something it is worth 
while for him to see or tell him something worth knowing and 
keep this up to the point of weariness; then let him rest; let this 
go on through the grades and nature study will have done for him 
its best. How many curious, inquisitive children and how few 
curious, inquisitive men ! Nature study, if anything, can remedy 
this. In the past, from the kindergarten or home to the high 
school or college, our instruction has been almost wholly in books; 
during this period, the pupil's confidence in his power to see often 
almost wholly disappears. Ask a class of a hundred freshmen 
to learn how many gills a crawfish has, and the many will go to 
the library, the few to the brook. What a blessing nature study 
would be if it could keep alive throughout the formative period, 
the child's native desire to know at first hand. It would give to 



Preface. ix 

the race as many Aristotles and Darwins as child endowments 
promise us. 



The child has tasks enough; tasks which he must not only do 
but remember for the quiz. Why not interest him in something 
without the imminence of a judgment day. Ten inspiring minutes 
twice a day and an outing twice a week, when the weather is 
suitable, with the blessed privilege which men universally enjoy 
of forgetting if he wants to, will put a spirit into all his tasks that 
will surprise every one in its results. The one big result will be 
that learning will become attractive.. 



I am under obligation to Prof. H. B. Dormer, of Purdue, for 
Figure 30. to Prof. J. F. Thompson, of the Richmond High 
School for Figures 29, 54, and 87, and to Mr. A. M. Mahaffy for 
Figure 139; to Miss Helen M. Fiske for several drawings and to 
Mr. George Bond, Mr. Vivian Floyd, Miss Ruth Trueblood and 
Mr. Charles H. Frazee for permission to photograph microscopic 
slides; all of these are credited in connection with the several 
illustrations. A few illustrations have been copied from different 
sources and are acknowledged in the accompanying cut legends. 
I am under special obligations to Prof. David M. Mottier, of the 
Indiana University, and to Prof. J. F. Thompson, of the Richmond, 
Indiana, High School, who have read all the proof. Their sugges- 
tions have been very valuable and I have been able to turn them 
all to account. I assume all responsibility, however, for both the 
subject matter and the method of presenting it. 

I take pleasure in adding to the list of books given on page VII 
of this preface at Prof. Mottier 's suggestion, Stevens' Introduction 
to Botany. D. C. Heath & Co. 

DAVID WORTH DENNIS. 

Earlham College, June, 1903. 



CONTENTS. 



Adaptation to Light. 

Lesson. Page 

I. The Disposition of the Branches of a Beech Tree 1 

II. The Tree Grown in the Open Country and the 

Forest Tree 3 

III. The Branching of a Fir-Tree 6 

IV. The Branching of the Elm 8 

V. Unequal Lighting 9 

VI. Pendant Branchlets 11 

VII. Horizontal and Vertical Branches 12 

VIII. The Behavior of the Petiole 14 

IX. The Behavior of the Petiole. The Maple Spray. . 15 

X. The Aspen. The Prickly Lettuce 16 

XI. The Shape of the Leaf-Blade 17 

XII. The Rosette Leaf -Arrangement 21 

XIII. The Stem's Main Duty 21 

XIV. The Sleep of Plants 24 

XV. The Leaf -Arrangement of the Beech Tree 27 

XVI. Leaf -Arrangement 28 

Pollination. 

XVII. Self-Pollination 32 

XVIII. Staminate and Pistillate Flowers. A Monoec- 
ious Species 33 

XIX. The Advantage which the Monoecious Species 

Has 35 

XX. The Dioecious Species 36 

XXI. Flowers in Avhich the Pistil Appears First 37 

XXII. Flowers in which the Anthers Appear First 38 

XXIII. Flowers and Insects. Bees 40 

XXIV. Flowers and Insects. Butterflies and Moths .... 41 
XXV. Symbiosis. — "Reciprocity." 42 

XXVI. How the Ants Are Kept Out 44 

XXVII. Flowers that Never Open 45 

XXVIII. Results of Experiments in Cross and Self- 
Pollinated Plants of the Same Species. ..... 46 

XXIX. Why Flowers Are Showy 47 

XXX. Why Trees Have Not Showy Flowers 48 



Contents. 



Adaptation to Climate. 



Lesson 

XXXI. 

XXXII. 

XXXIII. 

XXXIV. 

XXXV. 

XXXVI. 

XXXVII. 

XXXVIII. 

XXXIX. 



XL. 

XLI. 

XLII. 

XLIII. 

XLIV. 

XLV. 

XLVI. 

XLVII. 

XLVIII. 

XLIX. 

L. 

LI. 

LII. 

LIII. 



LIV. 

LV. 

LVI. 

LVII. 

LVIII. 

LIX. 

LX. 

LXI. 

LXII. 

LXIII. 

LXIV. 



Page 

Storms 49 

Annual Herbs 50 

Biennial Herbs 51 

Perennial Herbs. Solomon's-Seal 53 

Deciduous Forests 54 

Evergreen Leaves 55 

Buds 57 

The Persimmon Tree. A Special Case 59 

The Influence of the Wind 60 

The Leaf. 

The Foliage Leaf 62 

One Duty of Green Leaves 64 

Leaves in the Role of Spines 65 

Leaves in the Role of Bracts 66 

Leaves in the Role of Sepals and Petals 67 

Leaves in the Role of Stamens 69 

Leaves in the Role of Pistils 70 

Leaves in the Role of Bud-Scales 71 

Leaves in the Role of Bulb-Scales 72 

The Pappus of the Dandelion 74 

The Blossom End of the Apple 75 

Leaves in the Role of Tendrils 77 

How Tendrils Behave 78 

How the Bean Finds its Pole 79 



Seed Dispersal. 



The 



The Multitude of Plants. 

Existence 80 

The Winged Seed of the Linden 82 

Other Seeds with Wings 83 

The Dandelion's Parachute 84 

Other Pappus-Bearing Seeds 87 

Some Adaptations of the Thistle 88 

Smallness of Seeds and Spores 89 

The Spanish Needle 91 

Other Seeds that Cling 93 

Currents of Water 93 

Fruit. The Service of Animals that Eat it 94 



Contents. 



Lesson Page 

LXV. Nuts and Animals 95 

LXVI. Special Contrivances 96 

LXVII. Special Contrivances 98 

LXVIII. A Seed-Dispersal Table 99 

Plant Societies. 

LXIX. Water Plants 101 

LXX. Microscopic Plants 104 

LXXI. One Plant Adapted to Live in Water 105 

LXXII. Desert Plants 109 

LXXIII. Adaptation to Moisture. Land Plants Ill 

LXXIV. Some Advantages of Mass Life. Society Life ... 112 

LXXV. A Walk in the Woods. Forestry 113 

Stems. 

LXXVI. The Fibro-Vascular Bundle 115 

LXX VII. The Arrangement of the Fibro-Vascular Bun- 
dles in Exogens 117 

LXXVIII. Growth of Wood in an Exogen 119 

LXXIX. Quarter-Sawed Oak 123 

LXXX. Heart-Wood 124 

LXXXI. Stem Disguises 126 

LXXXII. Why the Yellow Violet Comes so Early in 

Spring 127 

LXXXIII. Bark 128 

LXXXIV. Ashes. 129 

LXXXV. The Root 130 

LXXXVI. Why Clover Helps the Soil 132 

Uses of Plants. 

LXXXVII. Plants and Starch 134 

LXXXVIII. Plants and Food 135 

LXXXIX. Plants and Clothing, Medicine, etc .136 

XC. Lumber and Fuel 15 7 

XCI. Parasitic Plants 140 

XCII. The Plant's Chief Work. Saprophytic Plants ... 144 

XCIII. Chlorophyll 146 



Contents 



Protoplasm. 



XCIV. Differences Between Animals- and -Plants 148 

XCV. The Respiration of Plants 150 

XCVI. The Cell 151 

How Plants Multiply. 

XCVII. The Asexual Way 152 

XCVIII. -The Sexual Way 156 

XCIX. Growth from the Cell to the Tree 164 

C. Cell Duties in a Many-Celled Plant 164 

CI. Young Plants 166 



NATURE STUDY. 



ONE HUNDRED LESSONS ABOUT 
PLANTS. 



LESSON I. 
Adaptation to Light. 

The Disposition of the Branches oj a Beech Tree. 

Figure 1 shows a beech tree in its winter condition. It 
will be noticed that its lower branches droop ; higher up they 
are horizontal; higher still they rise. Why is this? It 
cannot be that gravity alone makes the lower branches 
droop for it acts on all alike. Look more closely and see if 
the disposition of all the branches of the beech tree is not 
such as to get its leaves to the light to the best advantage. 
During all our observations on trees we should test the 
following: The one main purpose of the stem of the tree, 
its trunk and its branches, is to get its leaves to the light. 

Exercise: Every pupil should draw a beech tree as ac- 
curately as he can, but it should show the disposition of the 
branches above referred to. "A pencil is a good eye." 
Examine also a sun flower to see if it gets its leaves to the 
light in a similar manner ; do the petioles of the lower leaves 
droop ; and those of the middle leaves grow in a horizontal 
direction while those of the uppermost leaves rise? 



Nature Study 




Fig. 1. 

A beech tree showing how Jits branches get their leaves to the light; the lower 
droop, the middle grow straight, and the upper rise. 



Adaptation to Light 3 

LESSON II. 
Adaptation to Light. 

The Tree Groun in the Open Country and the Forest Tree. 

Visit a walnut, oak, ash, or wild cherry tree that has 
grown in the open country and one that has grown- in the 




Fig. 2 

This walnut tree grew in an open field; light called and its branches responded 
ni all directions. It was photographed at the same distance as Figure 3. 



4 Nature Study 

forest. How high is the tree in each case ? How high is the 
first branch ? It will be seen that in the open, every branch 
has responded to the influence of the light, has lived and 







% 



I -If 




Fig. 3. 

This walnut tree grew in the woods; light was to be had from above only; its 
lowest, shaded limbs died; it is a tall tree. 



Adaptation to Light 5 

has grown vigorously toward the light ; horizontal branches 
are sometimes found as large as considerable trees in the 
forest. In the forest, neighboring trees have shut out the 
light and the lower branches have died; the highest 
branches, called upward still by the light, have grown and 
grown until the result is what we call the monarch of the 
forest. Fig 2 is a walnut tree grown in a field; Fig 3 is a 
walnut grown in the forest. These photographs were made 
at the same distance from the trees and correctly represent 
their dimemsions. The circumference of Fig 2 is 9^ feet; 
that of Fig 3 is 43^ feet. So the country tree is much the 
older. The forest tree is, however, much taller and its 
lowest limb is much higher. In the pine forests of Europe, 
it is a business for some women, children and old men to 
cut off the under branches that have died in the shade and 
gather up others that have fallen and bind them in bundles 
for kindling purposes. 

Exercise : Find and draw a tree that has grown alone in 
the country and one of the same kind grown in the forest, 
care being taken to draw them to a correct scale. Measure 
both trees just as they grow. 



How to Measure a Growing Tree. 

First, measure the height of, your eye on the tree trunk, 
and mark the spot c. Walk back 100 feet from the tree to 
e and set up a pole between you and the tree so you can just 
see the top of the tree d over the top of the pole a. Mark 
the point on the pole b between your eye and the spot c. 
Now measure the distance ab ; we will suppose it to be 6 
feet. Measure the distance eb from your eye to b ; we will 
suppose it to be 10 feet. Now the distance dc is as many 
times ab as 100 feet is times eb. This is ten; therefore the 



6 Nature Study 

tree is 10 times 6 = 60; add to this the height of your eye, 
4 feet, and you have 64 feet, the height of the tree. Or if 
you understand it — eb:ec::ab:dc. 10: 100::6: height of the 
tree above your eye. 




LESSON III. 
Adaptation to Light. 

The Branching of a Fir-Tree. 

Figure 4 is a fir-tree. You can tell a fir-tree from a spruce 
or hemlock by its leaves which have no petioles, but are at- 
tached to the branch by a slightly enlarged disk. Notice 
how perfectly conical its top is; the light makes it so. Go 
under the tree, close to the trunk and look up. You will 
see that the branches are bare except at the extremities. 
The leaves have all died where they were in shadow. Be- 
cause the branches grow gradually shorter from below 
upward, the upper ones cannot shade the lower at their ends ; 
here the leaves grow. When a tree has one main branch 
from root to top as this tree has, we call its branching 



Adaptation to Light 7 

excurrent. But it is far less valuable for you to remember 
this than it is for you to understand that this is one way for 
every branch to get some of its leaves to the light. 




Fig. 4. 

A fir-tree; excurrent branching; every branch reaches 
above it and so all get the light. 



little farther than those 



Exercise : Find a fir-tree and sketch it to a correct scale ; 
go back to the beech again and see if its branching is also 
excurrent. See if you can find a fir-tree, the branches of 
which droop like those of the beech. 



8 Nature Study 

LESSON IV. 
Adaptation to Light. 

The Branching of the Elm. 

Figure 5 is an American elm in its winter condition. 
Notice that there is no main trunk above its lowest branches. 
Find the tree growing out by itself where every branch has 




Fig. 5. 
The elm; deliquescent branching. 

an equal chance at the light. When a main trunk divides 
up into two or more somewhat equal branches and these 



Adaptation to Light 9 

branches divide in somewhat the same way, we call this 
method of branching deliquescent. But the important thing 
for us to consider is whether every branch grows in the 
direction that will most quickly and certainly bring its 
leaves to the light. If the attraction of the light is the 
determining thing and there is a flood of it in all directions 
should we not expect a symmetrical top like this? 

Exercise: Draw the elm showing its manner of branch- 
ing. Find twenty different kinds of trees and determine 
for each of them whether the branching is most like the fir 
or the elm. Is the apple excurrent or deliquescent in its 
branching? The cedar? 



LESSON V. 
Adaptation to Light. 

Unequal Lighting. 

You are sure to see lack of symmetry in a tree, grown 
where one side is in light and one in shadow. Figure 6 
shows a pitch-pine that has grown in a clump of evergreens. 
The main branch on the light side is 18 feet long. The 
longest branch on the other side is only 4 feet. A wild 
cherry tree growing between a linden and a sycamore near 
my home, is flat because it is shaded on two sides and not 
on the other two ; its expanse from the light side to the light 
side is 40 feet while from the shady side to the shady side 
is only 20 feet. 

Exercise; Find a tree somewhere so grown that it has 
little light on one side ; it may be on the edge of a forest or 



10 



Nature Study 



on the outside of a group of trees or near a building. Meas- 
ure its expanse of branches and draw it to a scale. Find 




Fig. o. 

The pitch-pine; the branches on the shady side are to those on the sunny side 
in length as 4:18. 

enough such trees so that you will feel sure that the amount 
of light is one important thing in determining vigor and 
direction of growth. 

Consider the lilies of the field, how they grow. 



Adaptation to Light 11 

LESSON VI. 
Adaptation to Light. 

Pendant Branchlets. 

Notice Figure 64, Lesson XXXIX, and you will see that 
the circles of limbs are some distance apart; this leaves 
light spaces between them in which pendant branchlets 
have grown down and brought their leaves to the light. 
Find a Norway spruce and see that this is one of its char- 
acteristic habits of growth. You can tell a spruce from any 
tree that closely resembles it by the short, brown stems of 
its leaves. These pendant branchlets of the spruce give it 
a peculiar appearance in the distance. It should be one 
aim of our nature study work to name as many ti ees as we 
can by their figures at a distance of fortv rods or so. The 
European larch has the same habit. It can be told from 
the tamarack, the tree that looks most like it, by its pend- 
ant branches. 



12 



Nature Study 



LESSON VII. 
Adaption to Light. 

Horizontal and Vertical Branches. 

Figures 7 , 8 and 9 show three branches of Norway spruce ; 
7 grew directly upright ; 8 shows a side view, and 9 the view 
from below of horizontal branches. The vertical branch is 
round; the leaves grow on all sides of the branch; thev 




Fig. 7. Fig. 8 . Fig. 9. 

Fig. 7. A round spruce branch; it grew upright and had light in all directions; 
Fig. 8."was horizontal and is flat; if turned through 90 degrees it would appear as 
wide as 7 or 9. Fig. 9 was horizontal and is seen from below. 



Adaptation to Light 



13 



grow in like manner on all sides of the horizontal branch but 
the under leaves come around to the side in order to get to 
the light. The same lesson may be equally well learned 
from a hedge that is just ready to be trimmed; some of the 
long, fresh shoots will be found growing straight up, and, 

as there are eight rows of 
leaves on the stem it will 
appear round in full leaf, 
Figure 1 1 ; other branches 
will be found that have 
taken a horizontal direc- 
tion and the leaves of these 
will have crowded together 
\ on the two sides and the 
branches will appear flat, 
Figure 10. Apple or peach 
branches will show the 
same thing, only there are 
but five vertical rows of 
leaves on these branches. 
If a two -ranked stem like 
beech, elm or hazelnut is studied it will be found that on a 
horizontal branch the leaves lie in the plane of the branch 
— look at right angles to it. On a vertical branch so grown 
that its light comes from above the leaves have turned 
ninety degrees on their stems and face the tip of the branch. 
Examine and see if it is the petiole that brings the leaves 
into these varying positions. 

Notice that the lea\ r es of the spruce are short and narrow 
and that there are many vertical rows on the branches with 
the leaves close together ; the hedge has broader and longer 
leaves with fewer rows and the leaves in its rows much 
farther apart. Does this ratio hold generally for leaves; 
the wider and longer the leaves the fewer the rows and the 
farther apart? 




Fig. 10 



Fig. 11. 



Fig. 10, a hedge branch that grew hori- 
zontal. It is flat. Fig. 11, a hedge 
branch; it grew upright and round. Drawn 
from nature by Miss Helen M. Fiske. 



14 Nature Study. 

LESSON VIII. 
Adaptation to Light. 

The Behavior of the Petiole. 

Examine a pump kin -vine ; it will be found that the peti- 
oles that come out on the upper side grow straight and 
spread their leaves out directly above ; but petioles coming 
from the under side curve round and then grow out at the 
angle best suited to bring their blades to the light. 

Examine a morning-glory or any other sort of twining 
vine ; the petioles that leave the vine on the side next to the 
support all bend around so as to bring their blades to the 
light. Make the same study of a Virginia creeper growing 
on the side of a house. Is not the petiole of a leaf a con- 
trivance to bring the blade to the light? Does it not grow 
straight or crooked, long or short, up or down or out, in 
order that it may do this? Pull a branch from the Lom- 
bardy poplar; its branches cling close to the tree, — grow 
almost straight up. Have the petioles all brought their 
blades around so as to face the light? 



Adaptation to Light. 



15 



LESSON IX. 



Adaptation to Light. 



The Behavior of the Petiole. Maple Spray 



Figure 12 shows a maple 
spray. Study this figure 
with a maple spray before 
you. Study it at the tree; 
for the direction of growth, 
or the length of a petiole 
will often be determined bv 
the shadow of leaves on a 
neighboring spray or on 
neighboring trees. Com- 
pare the maple spray with 
thebeech spray. Lesson XV. 
Notice that on the maple 
branch there are four rows 
of leaves while on the 
beech branch there are but 
two. Notice again that 
beech leaves on the same 
spray cannot shade each 
other, that the maple 
leaves can and that they escape this calamity by the vary- 
ing length of their petioles and their direction of growth. 
It must be some trouble and expense to a leaf to grow a 
long petiole, and if nothing is gained by it why should it 
do so? Do not pass from this lesson till you can see why 
the beech does not need long and short petioles, while the 
maple does. Study Lessons IX and XV together. 




A maple 
petioles of lower leaves. 



Fig. 12. 

pray, showing the longer 



16 Nature Study. 

LESSON X. 
Adaptation to Light. 

The Aspen. The Prickly Lettuce. 

The aspen, the Carolina poplar, the Balm of Gilead, the 
Lombardy poplar and a few other rare poplars have the 
petioles of their leaves flattened vertically so that the leaves 
quiver in the slightest breeze. Study this feature of the 
aspen tree if possible. Scott, in order to tell how perfect 
the calm, says, 

"Scarce the frail aspen seemed to quake." 

This quaking permits the light to fall on leaves that other- 
wise would be in shadow. 

The common prickly lettuce furnishes an interesting 
study ; its leaves turn 90 degrees on their axes near the stem 
so that the leaf stands edgewise; they also turn so as to 
point in a general north and south direction from which it 
is often called the "compass plant." The effect of both 
these movements is to lessen the amount of light they re- 
ceive. We must not get the notion that the more light the 
better for a plant, for plants can get too much light as well 
as too little; in tropical and semi-tropical countries plants 
have many ways of dodging or tempering the extreme light, 
see Lesson LXXII and especially the cross-section of a 
purslane leaf, Figure 117. 



Adaptation to Light. 17 

LESSON XL 
Adaptation to Light. 

The Shape of the Leaf-Blade. 

Figure 15 is a leaf of a cut-leaved maple. Figure 12 shows 
leaves of the Norway maple. Go close up to the Norway 
maple and see it "as the squirrel sees it." Its branches are 
bare ; now visit the cut-leaved tree ; its branches are all cov- 



Fig. 13. Fig. 14. Fig. 15. 

Fig- 16. Fig. 17. Fig. 18. 

Figs. 13 and 17. Notched, pinnately veined leaves of yellow chestnut-oak 
Fig. 14. Round-lobed leaf of white oak. Fig. 15. Cut-leaved maple leaf. Fig 
16. Awned. lobed leaf of red-oak. Fig. 18. Pinnately compound leaf of clematis. 

ered with small branchlets, bearing many leaves. Is not 
the reason for this that the sunlight sifts through between 
the leaf -lobes of the cut-leaved maple, while the broad leaf 



18 



Nature Study. 



of the Norway maple shades the main branches so that 
leaves cannot grow on their branchlets? 

Exercise I : Estimate the number of leaves on a Norway 
maple and a cut-leaved maple of the same size. Have we 
not here on one tree a large number of leaves with small 




Fig. 19. Fig. 20. Fig. 21. 

Fig. 22. 

Fig. 19. Palmately compound leaf of horse-chestnut. Fig. 20. A chestnut leaf. 
Fig. 21. The palmately lobed leaf of the sycamore-maple. Fig. 22. A moun- 
tain-ash, odd-pinnately compound. 

working surface doing for one tree what a much smaller 
number of leaves with large blades do for another? 

When the thermometer is 100 degrees in the shade, try 
the shade of these two trees. Try the shade of the locust, 
ash, walnut or Kentucky coffee tree in the same way; all of 
them have pinnately compound leaves somewhat like 
Figure 22 . The light can filter through between the leaflets. 



Adaptation to Light. 



19 



The pine has needle-shaped leaves; has it more leaves 
than the sycamore? Try to estimate the number of leaves 
on trees about the same size. Try also the shade of the 
pine. The light can sift through between its needles to 
leaves below. 

Exercise II: Find young trees, five to fifteen feet high, 




Fig. 23. Fig. 24. Fig. 25. 

Fig. 26. Fig. 27. 

Fig. 23. Entire, heart-shaped leaf of lilac. Fig. 24. A greenbriar leaf showing 
stipules changed to tendrils. Fig. 25. A stipulate leaf of rose. Fig. 26. Oblique 
leaf of American elm. Fig. 2 7. Parallel- veined leaf of ginkgo. 

growing in the shadow of a forest. Why have they larger 
leaves than similar undergrowth where the light is stronger ? 
See if it is possible to make out a ratio between the size of 
the leaves and the intensity of the light; that is, that a 
larger leaf in a weaker light is required to do as much work 
as a smaller leaf in a stronger light. 



20 



Nature Study. 




Fig. 28. 

The rosette leaf -arrangement. A mullein of the first year 



Adaptation to Light. 21 

LESSON XII. 
Adaptation to Light. 

The Rosette Leaf -Arrangement. 

Figure 28 shows a mullein at the close of the first season 
of growth. Such a mullein can be found in October. Three 
things are to be noticed ; each leaf grows out between two of 
a lower circle ; the upper leaves are smaller than those below 
them so they do not shade them much ; the upper do not lie 
flat as the lower do and for this reason shade the lower less. 
How many leaves in the mullein, Figure 28, can get the 
light ? How many in the mullein you are now studying and 
comparing with the cut? Draw accurately, as to direction 
of growth and size, the leaves of the mullein you have found. 
The mullein, thistle, cabbage and many other herbs are bi- 
ennials; that is, they require two years to mature seeds. 
During the first season they store up the food which they 
will use the next in maturing the seed. A necessary part of 
the work of preparing the food stored in the root is done in 
the leaf, see Lessons XCII and XCIII. The October mul- 
lein is getting ready for the stalk and seeds of next year. 
Figure 54 shows the seed bearing mullein of the second year. 



LESSON XIII. 
Adaptation to Light. 

The Stem's Main Duty. 

The stem, (in the case of a tree, the trunk and branches,) 
holds the leaves up to the light ; this main duty imposes upon 
it the additional duty of bringing nourishment and moisturt 
up from the ground and of supporting the top againse 



22 



Nature Study. 



storms. It may be noticed that trees grown in rich soil 
have much larger and taller trunks and branches than those 
grown in poor soil; oak forests in sand, as those at Oak 
Bluffs, Mass., are barely a third as high as those of our 
northern states. As one travels toward the north, trees 
become smaller and smaller until they at last trail beneath 
the snow. One notices the same thing in ascending a 
mountain; our prairie sunflowers in western Indiana and 
Illinois are fifteen feet high or more ; as one goes west he sees 




Birches on Mt. Katahdin. 



Fig. 29. 
Photographed by Prof. J. F. Thompson. 



them becoming lower and lower until at Denver they are 
three feet ; as he ascends Clear Creek canon the same short- 
ening goes on; ascending Gray's Peak one comes to brook 
plains carpeted from the melting snows on one side to the 
melting snows on the other with apparently stemless flowers, 
the prairie sunflower and its congeners from the plains. 
This seems to indicate that the stem is a great convenience 
under favorable conditions such as our rich soil affords, a 
necessity to be sure for large growth, but not for existence 



Adaptation to Light 



23 



as^roots, leaves and flowers are. Varying conditions of soil 
and climate do not permit a plant to avail itself of the sun- 
light to the same measure, so the stem varies as its environ- 
ment varies. 

Exercise: Compare plants of the same species grown in 
different soils. When opportunity offers make the same 
observations while ascending a mountain. 




Fig. 30. 

Onions and corn growing in loam, clay, and sand to show influnece of soil. 
From the Proceedings of the Indiana Academy of Science for 1902, by Prof. H. B. 
Dormer. 



Figure 29 shows birches growing on top of Mt Katahdin, 
Maine. They are not small because they are young, but 
because the climate compels them to be. The main stem 
has become a rootstock from which the dwarf branches grow. 

Figure 30 shows on the left three onion plants, one grown 
in loam, one in clay and one in sand ; on the right are three 
stalks of corn similarly grown. The effect of soil need hardly 



24 Nature Study 

be commented upon. The conditions of moisture, tempera- 
ture and light were the same for all. 

Exercise: Try raising potted plants in different soils. 
Try the effects of various fertilizers on plants. The secret 
of variations giving the fine greenhouse plants is due some- 
times wholly to the fertilizer. 



LESSON XIV. 
Adaptation to Light. 

The "Sleep" of Plants. 

It will be shown, Lesson XCIII, that plants utilize sun- 
shine in their work by day. Stems and branches hold their 
leaves up to the light and each petiole grows so as best to 
bring its blade into proper relations to it. Figure 31 shows 
an Abutilon photographed on a sunny day at noon. Figure 
32 shows the same plant in the same situation at 10:45 p. m. 
Every leaf droops. The day expanse was 14 inches; the 
night expanse, 9 inches. 

Exercise: Grow squash, pumpkin, cucumber, etc., as 
potted plants and measure accurately the positions of their 
leafblades at midday and at midnight. The same measure- 
ments may be made on shrubs that grow in the yard. A 
good one to measure is redbud. Make also day and night 
examinations of bean and pea, growing in the garden. In 
the day time, every leaf is alert and adjusted to the light. 
Can it be that plants sleep and wake, work and rest? 

What causes the leaves to assume these different posi- 



Adaptation to Light. 



25 



tions ? We are accustomed to say that it is the stimulus of 
the light; but this Abutilon assumes the erect position before 
it becomes light. It begins to awaken about 4 a. m. and 







i 




*mh 


SPi^ 




'*'3fit\\ 




s. 








-.■•' 


p 



Fig. 31. 

Abutilon, photographed at noon. 



is fully awake when it is light (January, 1903). It wakens 
up in a dark room into which no ray of light comes, at its 
usual waking hour. 



26 



Nature Study. 



These night and day movements" of plants are called 
nyctitropic; they may be studied to advantage in clover 




Fig. 32. 

Abutilon, photographed at 10:30 p. m. 

and Oxalis. In Oxalis the leaves fall from the horizontal 
position until they rest against the stem; in clover on the 



Adaptation to Light. 2 7 

contrary two of the three rise and bring their upper faces 
together while the third leaf rises in such a manner as to 
cover the two somewhat. 

Campbell says these movements are to diminish the 
radiating surface and prevent the loss of heat, but the 
Abutilon, clover and Oxalis all make these movements in a 
room that remains at the same temperature. Whether the 
action was at first caused by the alternation of light and 
darkness or by day and night changes of temperature or by 
both, the habit is so established that the movement is 
carried on, for a time at least, at a constant temperature and 
in total darkness. 

Examine leaves also at midday on a very bright day and 
see if they respond to the stimuli and change their positions 
in the presence of too much light and heat as well as too 
little. 

LESSON XV. 
Adaptation to Light. 

The Leaf -Arrangement of the Beech Tree. 

An elm will do for this lesson as well. The leaf -arrange- 
ment and bud-arrangement, when no buds are suppressed, 
are the same for the same tree. The buds generally ap- 
pear in the axils of the leaves, that is, just above the 
attachment of the leaves to the stem. It will be seen that 
the beech spray in full leaf is flat, that the leaves grow on 
opposite sides only; that there are two rows of leaves only 
on each branch; that consecutive leaves are 180 degrees 
apart; that if a string is passed through a beech branch 
from a leaf to those above it in order, the third leaf is over 
the first as shown in Figure 33. By this arrangement no 
leaf -blade can ever shade another on the same branch. 
For this reason they do not need long petioles to bring them 
to the light. Notice that they do not have long petioles. 



28 



Nature Study. 



Test this proposition on every plant you can find: the 
petiole of a leaf has for its main duty the task of bringing 
thebladeto the requisite amount of light. Compare Lesson IX 




Fig. 33. Fig. 34. 

Fig. 33. A two-ranked beech branch. Fig. 34. A three-ranked birch branch. 
Fig. 35. A five-ranked apple branch. Fig. 36. A way to determine leaf -arrange- 
ment. Drawn by Miss Helen M. Fiske. 

Exercise: Draw a beech or elm branch. The drawing 
should show for the purposes of this lesson that the petiole 
is very short and that the leaves are two-ranked. 



LESSON XVI. 
Adaptation to Light. 

Leaf- Arrangement. 

In previous lessons reference was made to the two- 
ranked leaves of beech, the eight-ranked leaves of hedge 
and the five-ranked leaves of apple. It was necessary to 
do this in order to study the light adaptations. 

Exercise I: Get straight young branches of elm, beech, 



Adaptation to Light. 



29 



mulberry, and hazelnut and compare them with Figure 33. 
This is the simplest of all leaf -arrangements. There are two 
leaves in one round; the leaves are 180 degrees apart and 
there are two vertical rows on the stem. Notice now that 
the arrangement of the branches is the same on those trees; 
notice that the bud-arrangement is the same ; that buds and 
1 ranches are alike just above leaves; this position of the 




Fig. 37. Fig. 58. 

Fig. 37. A thirteen-ranked pine cone. After Gray. 
Fig. 38. A five-ranked tamarack cone. After Gray. 

branches can be seen more easily on some branching annual 
like the clematis or ragweed. 

Leaves, then, have positions in which they grow; so have 
buds and branches ; this has reduced the study of disguised 
leaf forms to a science instead of a notion. Position is the 
determining element. It is important for the student to 
learn this. 



30 



Nature Study. 



Exercise II. Get short, straight, young branches of 
birch and also some of the tall, rough, triangular sedge 
grasses ; cut these off very close to the ground and examine 




Fig. 39. 

A cabbage-palm — Melbourne, Fla. 

the sheathing leaves at the base. Compare their leaf -ar- 
rangement with Figure 34. Notice that there are three 
leaves in a round, that any two consecutive leaves are 
therefore one-third of 360 degrees, or 120 degrees apart. 
This will be much more difficult than exercise I. If you 



Adaptation to Light. 31 

fail try exercises III, IV and V first and then return to II. 

Exercise III. Get straight water sprouts of peach, 
cherry, plum and quince and cones of the larch and tama- 
rack. Compare them with Figures 35, 36 and 38. Pass a 
string as shown in the cut. Notice that the sixth leaf is 
over the first; that the string to reach the sixth must pass 
twice around the stem. There are then five leaves in two 
rounds; or the consecutive leaves are 2-5 of 360 degrees, 
that is 144 degrees apart. 

Exercise IV. Get similar branches of hedge, holly and 
plantain and compare them with Figure 1 1 , and make cal- 
culations as before. How many rounds does the thread 
make before reaching the leaf directly over the first ? How 
many leaves does it pass? What is the angular distance 
between consecutive leaves? How many vertical rows are 
there on the stem? 

Exercise V. Get a cone of white pine and make out the 
arrangement in Figure 37 and make calculations as before. 
Answer the questions for the white pine given at the close 
of Exercise IV. 

Notice that all these different leaf-arrangements are so 
many ways plants have to accomplish the one purpose of 
getting their leaves to the light. Figure 39 is a cabbage- 
palm. What has its trunk to do with getting its leaves to 
the light? The long petioles of the leaves? The arrange- 
ment of the leaves? The frayed out ends of the leaves? 

"Next to moisture, light is the most powerful external 
factor in giving shape to plants. Warmth sets the machin- 
ery of the plant in motion and regulates in the highest de- 
gree its development and activity but does not affect form. 
Light, as also water, exerts a commanding architectonic 
influence in the upbuilding of the plant body." — Schimper. 
Plant Geography as Influenced by Light. 




32 Nature Study. 

LESSON XVII. 
Pollination. 

Self- Pollination. 

Figures 40 and 45 show flowers 
with sepals, petals, stamens and 
pistils. In Figure 40 the stig- 
mas are recurved and at the 
center. Every one has seen the 
f owder, often yellow, which the 
stamens bear. Figure 41 and 
42 show photographs of some of 
this dust taken with a micro - 
Fi s- 4o - scope ; the figures show the grains 

A complete flower; three sepals, . . ., .. 

the smaller outer leaves; three many times as large as they 

petal?, the longer inner leaves; six .... 

stamens and a pistil of three united really are. 

carpels having three recurved rrv1 . 1 n i 

stigmas. After Gray. These grams of powder are called 

pollen. It has often been shown that plants will not bear 
seeds unless this pollen falls on the stigma of the pistil. 
This process is called pollination. Figure 41 shows i pollen- 
grain, the wall of which has opened and the co it ants of 
which are growing down through the top of the style toward 
the ovary. It does not cease to grow dc^n until it reaches the 
egg-cell of the ovary when one of the pollen nuclei unites, 
with the egg-cell and fertilization is complete. When the 
stamens that furnish the pollen grow in the same flower 
with the stigma on which they fall, we call the process self- 
pollination. When the stamens grow in one flower and the 
stigma on which their pollen falls g "ows in another flower, 
we call the process cross-pollination. Flowers which have 
both stamens and pistils are perfect flowers. 

Exercise: Find a half dozen kinds of flowers that are per- 
fect. Count the stamens and stigmas in each so as to b? 



Pollination. 



33 




Fig. 41. 

Two pollen-grains that have alighted on a stigma of purslane; their pollen- 
tubes are growing down toward the egg-cell in the ovary. From a slide by Mr. 
Vivian Floyd, x 300. 

sure the flower has both and sketch them, showing just the 
right number. 



LESSON XVIII. 
Pollination. 

Staminate and Pistillate Flowers. A Monoecious Species. 

If a flower contains stamens but no pistils, we call it a 
staminate or sterile flower. There are manv such flowers in 



34 



Nature Study. 



a single tassel of corn. If a flower contains pistils but no 
stamens we call it a pistillate or fertile flower. The silks 
that corn bears where the ear is to be, are parts of fertile 
flowers. 

We name all those plants that we think sufficiently re- 




Fig. 42. 

Pollen-grains of white pine with an air balloon at each end. x by about 400. 

semble each other to have descended from a single seed or 
from common parents, a species. Corn, the marsh-mari- 
gold and the red maple are examples of species. When the 
staminate flowers grow on one part of a plant and the pis-, 
tillate on another, as in the case of corn, we call the species 
a monoecious species. When the stamens grow on one 
plant and the stigmas on which the pollen falls grow on 



Pollination. 3 5 

another, we have cross-pollination, in which different in- 
dividuals take part as well as different flowers. Yellow and 
white corn will, as is well known, mix across a road; this is 
because pollen from the tassels, the stamen bearing flowers 
of one kind, falls on the stigmas of the other kind. It is 
said that it will not do to plant watermelons and pumpkins 
in the same patch; the pollen from the pumpkin blossoms 
will get on the stigmas of the watermelon blossoms and the 
melons will be ruined. Broomcorn and cane cannot, for 
similar reasons, be raised near each other. These are cases 
of cross-pollination between different species. Cross-polli- 
nation between individuals of the same species seems to 
result in stronger plants. Many experiments have been 
tried that show this; see Lesson XXVIII. We would be 
justified in concluding that it is so because nature has 
taken such pains to bring cross-pollination to pass. 



LESSON XIX. 
Pollination. 

The Advantage which the Monoecious Species Has. 

The tassels containing many staminate flowers grow on 
the top of the corn stalk ; the chances are that the pollen will 
be carried by the wind obliquely and that it will reach the 
pistil of some other stalk and so produce cross-pollination 
between flowers of two individuals. If the pollen grew in 
the same flower with the silks this would be far less probable. 
It may be said that the monoecious arrangement favors 
cross-pollination from plant to plant and is therefore a help. 
The ragweed furnishes another fine illustration of this. 
The sterile flowers grow in long racemes at the top of the 
weed. It is a habit some boys have to scrape up between 



36 . Nature Study. 

their fingers the yellow dust and its receptacles from the 
sterile flowers. Where do the fertile flowers and seeds of 
the ragweed grow? At least they grow somewhere lower 
on the weed than the sterile flowers do. The wind carries 
the pollen everywhere and doubtless effects cross-pollina- 
tion from plant to plant generally. 



LESSON XX. 
Pollination. 

The Dioecious Species. 

It often happens, as in the case of the mulberry, that all 
of the trees do not bear seeds. This may be because one 
tree bears only pistillate flowers and the other only stami- 
nate flowers. The first kind is said to be a fertile, pistillate 
or female tree, the second a sterile, staminate or male tree. 
A pistillate tree will only bear when there is a staminate 
tree somewhere near enough to send pollen to its stigmas. 

Exercise: Find a mulberry tree that bears and see how 
far it is to a pollen bearing tree. It would manifestly aid 
the wind in bearing the pollen long distances if the pollen- 
grains were winged. This is often the case. Figure 42 
shows the winged pollen-grains of white pine. 

Herodotus makes note of the fact that the Egyptians had 
a yearly festival, in which they went to the desert and 
brought sterile palm branches and waved them over the 
fertile trees they had planted along the Nile. By this 
means they could give all their space to the growing of trees 
that would bear. It would be interesting to know how they 
came by the knowledge that such action would cause fruit 
to grow, long before we knew the office of pollen in fruit 
production. 

Exercise: See if box-elder is a dioecious species. Is red 



Pollination. 3 7 

Cedar? Is Ailanthus? Is the Persimmon? Is any willow 
you know? 

The plain advantage of the dioecious arrangement is that 
cross-pollination is the only kind that can occur ; but it 
seems to be a law that every adA^antage has its accompany- 
ing disadvantage ; the disadvantage in this case is that only 
part of the trees can bear fruit. 



LESSON XXL 
Pollination. 

Flowers in which the Psitil Appears First. 

Common plantain is a weed every one knows; it has a 
rosette of tough broad leaves from which it sends up a long 
spike of flowers. This spike blooms from the bottom up. 
In any given flower the pistils ripen before the stamens do ; 
it is therefore entirely impossible that any stigma should 
receive pollen from a stamen in the same flower. Protogynv 
is the term we use to describe this arrangement; the word 
means pistils blooming first. This is one of many ways bv 
which nature provides for cross-pollination. If the lowest 
flowers on any stalk are fertilized at all it must be with pol- 
len from another plant ; it is often doubtless true that higher 
stigmas receive pollen from other plants. That the ripe 
pistils are above the ripe stamens favors this. The growth 
of the plants in societies also favors it. 

Some species of plantain may be found blooming all 
summer long. Sketch a spike when the ascending circle of 
protruding stigmas has reached the middle of the stalk with 
the circle of stamens below it. 



38 Nature Study. 

LESSON XXII. 
Pollination. 

Flowers in which the Anthers Appear First. 

The fire weed, Epilobium, is not so common as the plan- 
tain. I have, however, seen it blooming in many parts of 
the country, late in August. Its time for blooming is given 
from July to September. It has a pink-shaped blossom 
with a reddish-purple color. It is some four feet high and 
very striking. Its anthers come out first, the stigma being 
bent quite out of the way, and discharge their pollen and 
wither ; the pistil now becomes erect ; the anthers of its own 
blossom having withered, only cross-pollination can occur; 
bees carry -pollen from one flower to another and thus pro- 
duce cross-pollination. 
Fig. 43, after Gray, 
shows the ripe stamens 
and the recurved, un- 
ripe stigma. Figure 44, 
Fig. 43. Fig7"44. also after Gray, shows 

Fig 43 Fireweed blossom; stigma green and t ^ e erect T ^ e stigma 
recurved, stamens ripe. Fig. 44. Fireweed; stig- ir ou & "" 

ma ripe and erect ; stamens withered. After Gray, arid withered stamens 

Figure 45 shows two blossoms of Amaryllis. The one on 
the right has ripe stigmas and withered stamens; the one 
on the left unripe, recurved stigmas and ripe stamens. 
Notice the white stigma quite below the anthers in front of 
a petal. Notice that it is not divided. Nine days later 
when its own stamens were wholly withered it had bent up 
to about their position so that an entering insect would 
brush it and its three stigmas were fully ripe and unfolded. 
The stamens being now mature in the left blossom are in a 
position to be brushed by an entering insect. 




Pollination. 



39 




Fig. 45. 

Two blossoms of Amaryllis; the stamens and pistils show the same thing as 
Figures 43 and 44. 





40 Nature Study. 

LESSON XXIII. 
Pollination. 

Flowers and Insects. Bees. 

A fine beginning of the study of this relationship can be 
had by the careful study of the parts of a bean blossom; 
after which the visits of the bees to the blossoms must be 

watched. The wings of 

the bean blossom (l),Fig- 

' ure 46, furnish a landing 

place for the bee ; it must 

Fig. 46. Fig. 4/. land here in order to get 

Fig. 46. A bean blossom; 1, the wings on fU^ "hnnPAr TVip cKr1p> 

which the bee lights. 2, the keel in which Llie UUIiey • iue bLVlt!, 

are the stamens and pistil. After Gray stigma and Stamens are 

Fig. 47. Bean blossom. The weight of the ° 

bee on the wings causes the stigma 1, and enclosed in the keel. The 
the hairy, pollen-laden style 2, to come out 

of the keei.The stigma strikes the bee ^and picks stamens early shed their 

up pollen from another flower. The blow J 

makes its own pollen fall from the style en po llen which lodges On the 

the bee for the next flower he visits. After r fc> 

Gray - hairy style near the stig- 

ma, Figure 47. The weight of the bee on the wings presses 
the style and stigma out in such a manner that the stigma 
picks up pollen from the bee's body that came from another 
flower and at the same time the style scatters down on 
the bee its pollen to be carried to the stigma of the flower 
next visited. 

Exercise: Press down on the wings of the bean blossom 
where the bee must light and watch the naked stigma and 
pollen-laden style come out. Cipher out the entire machin- 
ery and watch the bee's visit. . 

GLEICH UND GLEICH. 

"Ein Blumenglokchen A tiny hare bell 

Vom Boden hervor, In the meadow grew up 

War fruh gesprosset And hung out enchanting 

In lieblichem Flor; Fts little, blue cup; 

Dan kam ein Bienchen A bee came and sipped 

Und naschte fein: Of its sweets daintily; 

Die mussen wohl beide They must for each other 

Fur einander sein." Be flower and bee. 
Goethe. 



Pollination. 



41 



LESSON XXIV. 
Pollination. 

Flowers and Insects. Butterflies and Moths. 

Adaptations between flowers and insects to produce cross- 
pollination are very numerous and common. Some of them 




Fig. 48. Fig. 49. 

Fig. 48. Head of a moth. Its long tongue enables it to reach the nectary of 
an orchid shown in 2, Figure 50. Pollen masses 1, of Figure 50, adhere to the 
moth's eye by the disk; they are thus carried to the flowers subsequently visited. 
Fig. 49, the pollen masses by their gravity, turn down so as to reach the stigmas 
of flowers later visited. After Gray. 

Fig. 50. An orchid blossom, after Gray. Its pollen mass adheres to the moth's 
eye by a glutinous disk, 1, while the moth is getting nectar. 

are very complex and interesting, as, for instance, the lady 's- 
slipper, which will only let a bee out of the "slipper" along a 
road that forces it to rub first against the stigma and pollin- 



42 Nature Study. 

ate it and then against the stamens and gather pollen for the 
next flower. The relations between certain other orchids 
and moths are as remarkable. 

Figure 50 shows one of the orchids. The nectar is at the 
bottom of the long spur 2. The moth's tongue is just the 
instrument to reach it there. The opening into the nectary 
is so small that ants cannot enter ; this is the case with many 
flowers ; ants have no wings ; they cannot fly from flower to 
flower and carry pollen for cross-pollination ; it is therefore 
as necessary to keep ants out in some way as it is to attract 
bees, butterflies and moths. 

Notice the flower again ; at 1 there is a glutinous disk that 
carries many pollen-grains on a long stalk. These two disks 
are so situated that when the moth is taking nectar they will 
touch and adhere to its eyes as shown in Figure 48. Gravity 
then pulls them around to the position shown in Figure 49. 
When the moth visits succeeding flowers these will be 
thrust down to the concealed stigmas and cross-pollination 
will take place. Coordination is common between the vari- 
ous parts of one animal or plant, as for instance the tiger's 
claws and teeth go with the savage disposition; but here 
moth and flower fit each other like the nose and the specta- 
cles. How came this fitness to pass? The way to study 
this question is to notice from year to year carefully all 
similar relationships and see if they do not finally fall into 
a system. 



LESSON XXV. 
Pollination. 

Symbiosis . — " Reciprocity . ' ' 
Bees get pollen and nectar for the hive from the flowers. 



Pollination . 



43 



Flowers get the inestimable advantages of cross-pollination 
from the bees. The relationship is one of mutual helpful- 
ness. Symbiosis means life together. Butterflies and 
moths get nectar and pay for it with service in cross-polli- 
nation. The world of life is full of instances like this. 
The raspberry and cherry feed the bird and the bird plants 
their seeds in distant soils. The kingfisher digs the hole in 




Fig. 51. 

A cross-section of lichen, showing its compact upper and lower layers to prevent 
drying out; its inner reservoirs for moisture, 1, and the symbiont within 2, the 
round, black cells. Their real color is green. 



the bank and the bumble-bee has been known to occupy it 
with him and keep the small boys and other enemies away. 
The rattlesnake and the prairie-dog sometimes live together 
for similar reasons. The lichen has imprisoned a green 
plant between its leathery exteriors. The lichen holds the 
green plant up to the light, gives it support and protects 
it from the drought on rock or tree, while the green plant 
gathers food for both. 

Exercise : Cut a lichen in two with a sharp knife or razor 



44 



X at lire Study. 



and notice the green strip between the two white ones. 
Figure 51 is a photograph of a cross-section of a lichen and 
its imprisoned alga. The alga has been taken from the 
lichen and reared separately ; so it is an independent plant. 
What is the relationship between man and the domestic 
animals and plants? That is, are man and corn mutually 
helpful? Are men and horses? 

LESSON XXVI. 

Pollination. 

Flowers and Insects. How the 
Ants Are Kept Out. 

One common way is given 
in Lesson XXIV. There are 
several other ways ; the plant 
is sometimes surrounded by 
a water cup, — the teazel is 
an example. It sometimes is 
covered with bristly, down- 
ward pointing hairs in some 
part; sometimes these hairs 
are sticky and impede or 
even catch the ant; some- 
times the plants are slick and 
the ant, in her efforts to stick 
on, pierces the skin of the 
plant and a viscid juice turns 
her back or catches her; 
Fig 52. sometimes the flowers are 

Cyclamen blossoms. The flower nods nodding and she Can't Crawl 
and the floral envelopes turn back up 

in such a manner that the entrance of down to the edge of the COr- 
ants or rain into the blossom is impos- . 

sible. The lines in the petals shown olla Or Calyx limb and Safelv 
in the blossom to the right were caused J 

by eosin absorption. turn and crawl back up to 

the nectar ; sometimes the nectar is shut in and the door will 




Pollination. 



45 



not open except to the knock of the friendly bee. 

Exercise: Be on the watch for all these methods of ar- 
resting the ant. See if you can find a smartweed that grows 
both on land and in water, having a water cup to keep ants 
away when it grows out of the water, which it leaves off 
when it grows in water. Read chapter III of Sir John 
Lubbock's "Ants, Bees and Wasps." 

LESSON XXVII. 
Pollination. 

Flowers That Never Open. 
Pollination sometimes occurs in a closed flower. This 
must always be self-pollination. The anthers that furnish 
the pollen and the stigma on which it lodges must belong 
to the same flower. 

Exercise: In the spring, 
examine every sort of violet 
that you can find, especi- 
ally those that seem to 
have no stems; you will 
find a second kind of blos- 
som concealed by the leaves 
hard to find, but which 
bears nevertheless, more 
seeds than the flowers you 
have always known, Figure 
53. These blossoms never 
open. There are flowers 
belonging to sixty different 
genera that are self-polli- 
nated without opening. 
Cleistogamy is the name 
given to self-pollination in 

Large pods of cleistogamic flowers, 2, and rdncArl Anw^rc 
pods of other ordinary flowers opened, 1. LiUbeu liuweib. 




46 . Nature Study. 

Some of the advantages of cleistogamy are : 1 . Pollina- 
tion is sure to occur. 2. It is not necessary for the flower 
to provide so much pollen. A cleistogamic flower grows 
some 400 grains of pollen ; flowers which depend on insects 
to carry their pollen produce many times 400 and other 
kinds of plants yet to be described, see Lesson XXX, so 
many that the number can be estimated, not understood. 
Here, as elsewhere, advantage and disadvantage are bal- 
anced. The cleistogamic plants are weak. It is believed 
that they lack a factor that is necessary to their higher 
development. For some unknown reason, copulating cells 
from individuals of a species diverse in their origin give a 
strength and variety not otherwise to be had. Many sim- 
ple plants and animals reproduce by division of the parent ; 
but these do not improve ; they live on and on at one dead 
level. Some eggs will grow into new individuals without 
fertilization; we call the process parthenogenesis, but the 
parthenogenetic species does not improve from generation 
to generation. A capital exercise for any one provided 
with a microscope would be, to estimate the number of 
pollen-grains in a cleistogamic flower of violet, an anemo- 
philous flower like pine and an entomophilous flower like 
clover. 

LESSON XXVIII. 

Pollination. 

Results of Experiments in Cross and Self- Pollination Plants 
of the Same Species. 

Darwin raised 73 morning-glory plants from seeds pro- 
duced by cross-pollination and in the very same soil 73 
plants from seeds produced by self-pollination ; these sets of 
73 plants both belonged to ten generations. The height of 
the first 73 was to the height of the second 73 as 100 to 77. 
So the crossing made stronger plants. 



Pollination. 47 

His crossed and not crossed plants of the ninth generation 
bore seed by weight as 100 to 61 . These experiments con- 
firm what we should expect from the fact that nature takes 
such pains to produce crosses and the further fact that 
crossing actually takes place among all higher plants. 

Exercise : Cut the tassels from a few hills of corn before 
it ripens so that you can be sure cross-pollination from 
plant to plant, must occur. Dust the pollen from its own 
tassel on the silks of a few other stalks in the same row 
growing clo^e by and see which makes the best corn. 

LESSON XXIX. 

Pollination. 

Why- Flowers Are Showy. Fntomophilous Plants. 

The word entomophilous means insect-loving. It is 
applied to all those plants that depend on insects to carry 
their pollen. Such plants have bright colored flowers. 
Examples are red clover, white clover, morning-glory, 
hollyhock, snapdragon, Catalpa, etc., all showy flowered 
plants, all plants the flowers of which attract general atten- 
tion. It is believed that they are showy in order that the 
insects may see them. Why should they provide pollen 
and nectar for the insects and then not inform the insects 
in some way where they are ? The odor of the flower serves 
the same purpose ; a single flower might grow where the bee 
could not see it; in this case the odor alone tells the tale. 
We learned in Lesson XXVII that flowers that never open 
are inconspicuous. They are so inconspicuous that al- 
though they grow on our well known and universally loved 
violets, very few people indeed ever saw them. No doubt 
it is greatly to the advantage of flowers that do not depend 
on insects to help them to be inconspicuous. 



48 Nature Study. 

Exercise. Keep a list all summer long of the plants you 
see visited by insects. See if you can find out how it is 
necessary for the insect to become covered with the pollen 
and, also, to brush it on the stigmas % of the flowers they 
afterward visit. 



LESSON XXX. 
Pollination. 

Why Trees Have Not Showy Flowers. Anemophilous Plants. 

The word anemophilous means wind-loving. It is applied 
to all those plants that depend on the wind to carry their 
pollen. This includes most of the forest trees north of the 
Ohio river. Most people do not know that our beeches, 
oaks, hickories and pines, etc., ever bloom at all, but if we 
examine them in the spring we shall find that they produce 
countless millions of pollen-grains; enough, so that a single 
tree can give them to the wind and fill all the air for long 
distances. The trees are tall; they can take advantage of 
the wind as low herbs cannot. It is a considerable tax on a 
plant to produce large, showy blossoms. Why should they 
do this when they have a perfectly adequate way to get all 
done that insects could do? 

Exercise: Make a list of anemophilous plants. You 
may at first write in this list all plants with inconspicuous 
flowers, then notice to see whether bees visit them and if 
they do, note this fact. You cannot learn too soon that all 
our distinctions and dividing lines are artificial and for our 
convenience. You can not help observing, if you look, 
that many plants are crossed both by wind and insects and 
that self-pollination often occurs by the agency of both 



Adaptation to Climate. 49 

insects and wind and also in the very same plants without 
the agency of either of them. Let apparent inconsistencies 
be an incentive to you to look again. Sooner or later you 
will find that the sum total of the influence of wind and 
insect is to produce cross-pollination. 

LESSON XXXI. 
Adaptation to Climate. 

Storms. 

Stand by the window and watch a tree when the fiercest 
storm is on ; see how trunk and branches and leaves, if there 
are any, yield to the storm. Where is the strain greatest? 
Is it not just at the ground? And yet is not this just the 
place where a sound tree never breaks? Did you ever try 
to split a stump ? When the sound tree must fall does it not 
always break a few feet above the ground or else blow up 
by the roots? How does it come that the strongest place 
in a tree is the place of greatest strain and danger ? Watch 
a very small tree, only two or three years old, in a storm. 
Does it not yield to the strain, even to the extent of bending 
over to the earth sometimes? Would this not have a 
tendency to twist the grain at the ground and make the 
grown tree stronger there? The storm then strengthens 
most where it threatens most. 

Try to split a tree that has grown for a long time on the 
edge of a forest on the windward side and another that has 
grown in the middle of the forest; which splits the more 
easily ? Why ? 

In parts of Europe, large areas are planted in trees. Hills 
and mountains are kept covered in this way by forests. As 
one ascends the Brocken he sees everv few hundred feet, a 



50 Nature Study. 

small, fenced area. Trees are being sprouted in these to he 
planted out subsequently at the same altitude. They are 
raised from the start, subject to the same tempests, rairs 
and temperature that will surround them when they are 
trees, and in the same kind of soil. 

LESSON XXXII. 
Adaptation to Climate. 

Annual Herbs. 

In the northern United States, the growing season is 
practically between March and November. During the 
winter the temperature may fall to 20 degrees or more below 
zero. Most indigenous plants have habits which especially 
adapt them to this. Consider a tender herb like the rag- 
weed ; as winter approaches, it must cover itself with a cloth- 
ing that can resist this cold and the accompanying wet, or 
die. I presume most of us think it dies, but that is net 
quite the case. It selects a small part of itself which we 
call the seed, to which it gives a covering adequate to with- 
stand all the exigencies of winter and keep the embryo 
within alive. To have protected its entire body or even 
the main part of it would have been very expensive and, 
although some plants do this, if all plants did it we would 
have to have far fewer plants for there would not be room 
for them in the world. 

One way then to meet the conditions of winter is to reduce 
life to the compass of the embryo and wrap it up securely 
with the food necessary to start it in the spring. 

The beans we eat, the corn, the wheat, contain an embryo 
in every grain. Every one of them is a plant reduced to 
its winter condition. 

Exercise: Make a list of fifty plants that live through 



Adaptation to Climate. 51 

the winter in their seeds only. In making this list, you 
must know from careful examination that the root as well 
as the top, dies. While this is true of the mullein or thistle 
that bears seed, it is not true of all mulleins or thistles. 



LESSON XXXIII. 
Adaptation to Climate. 

Biennial Herbs. 

A biennial plant is a plant that lives for two years only ; 
that requires two years to bear seed. The root in all cases 
survives the first winter and the seed the second. The 
thistle, mullein, dandelion, turnip and cabbage are examples. 
The mullein does not grow a long stem the first year. This 
is an adaptation to the winter it must pass. It grows flat 
on the ground, Figure 28, and has a thick covering of 
branched hairs. These may serve to temper the light of 
the sun ; to hold dampness away from the surface of the leaf 
so that when it freezes it makes a cloak to keep the leaf 
warmer than it would be if naked, to check transpiration, 
or to protect the mullein from enemies that would otherwise 
eat it. The chief adaptations of the wild biennials like the 
mullein and thistle, to climate are that they grow only a 
short stem the first year, and they shrink to the dimensions 
of seeds the second. 

Exercise: Make a list of biennial herbs. Watch marked 
plants and see that they die when they seed at the end of 
the second year. Figure 54 shows a two-year-old mullein 
at seeding time. Compare it with Figure 28. 



52 



Nature Study. 



' .■■*&> ''<>"»>* •'IR^fRi 



Sfc*'^ 



yi£& 



? mm*® 







Fig. 54. 

A two-year-old seed-bearing mullein. Photographed by Prof. J. F. Thompson. 



Adaptation to Climate. 



53 



LESSON XXXIV. 
Adaptation to Climate. 

Perennial Herbs. Solomon s-Seal. 

You must know this interesting plant if you do not. 
Figure 55 shows the underground stem with its peculiar 
seals, the places where the plant grew in previous years, and 
a terminal bud. The seals mark the place from which the 




Fig. 55. 

Underground stem of Solomon's-seal. The scars or "seals" are shown above 
where the above-ground stem grew one, two, three and four years ago. 

aerial stem broke off last year and for the three years before. 
The root-stock is dying at the left. Its adaptation to win- 
ter manifestly is that it dies down to the ground at its 
approach and lives only in its underground stem and its 
seeds. 

Exercise: Make as long a list as you can of plants in 
your vicinity that live through the winter by dying down 



54 



Nature Study. 



to the ground only ; it may help a little to ask, do ferns do 
this? Does bloodroot do it? Does blue-grass? 



LESSON XXXV. 

Adaptation to Climate. 

Deciduous Forests. 

The falling of the leaves in autumn is one of nature's 
great phenomena. To one born in the tropics, where verd- 




Fig. 56. 

A cross-section of a deciduous leaf, a fern leaf; a stoma is shown open below. 
All the cells between the two layers of epidermis are working cells as their chloro- 
phyll granules show, x by about 200, 

ure is perennial, nothing is more striking. We are used to 
it and the strange thing for us would be for them not to fall. 



wmm 



Adaptation to Climate. 55 

The falling of the leaves is a preparation for, an adaptation 
to winter. 

Two choices are open to a tree : one is to so cloak its leaf 
surface that it can resist the cold of winter; the other is to 
shed its leaves. Each plan has its advantages and disad- 
vantages; each has been followed by successful species. 
The sycamore saves itself the trouble and expense of pro- 
tecting its leaves by shedding them ; but when spring comes, 
it must spend many days of its precious time in getting its 
leaves back again ready for work. Figure 56 is a cross- 
section of a leaf that perishes as winter approaches ; notice 
how thin is the outside protecting envelope. One of the 
stomata for admitting air is shown, open below. All the 
cells between the upper and lower layer are working cells. 
They are supplied with sap by means of the leaf's veins, one 
of which is shown near the middle of the section. 

Exercise: Collect a half dozen different kinds of ever- 
green and as many deciduous leaves and see which will tear 
the easier. 

LESSON XXXVI. 
Adaptation to Climate. 

Evergreen Leaves. 

The pine has taken the second plan, mentioned in the last 
lesson: it protects its working cells. Notice again, how 
tough its leaves are. Find out anew that its outside cover- 
ing is tougher than that of the leaves of deciduous trees. 
Figure 5 7 is a cross-section of the half of a leaf of the Scotch 
pine. You can tell this tree because it has reddish branches ; 
it has leaves about three inches long and two in a bundle. 
Its leaves are covered with a white powdery substance and 
have a grayish green appearance. Notice how thick are the 



56 



Nature Study. 



walls of the outside row of cells and also of the cells next to 
it except in the places where the leaf mouths for the ad- 
mission of air are. Notice that this second layer is three 
cells thick at the corners. It would be difficult to find any- 
thing more remarkable in its adaptations, its fitness, than 
the pine leaf is. The cells from the protecting outside layers 



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'w-tT'd; 1 ^V'if r^?'> v i^-K^sL, ~* .- i ,v ^o^y ".■■ >u.ii 




fli s ' ^^ ■ y-^5^^^?^ - : ^^kj 


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Fig. 57. 

A cross-section of pine leaf. It shows from without in, 1, a thick walled epider- 
mis; 2, a thick walled hypodermis, both pierced by the stomata; 3, chlorophyll- 
bearing cells, to be known by their infolded wal s. They contain a resin duct, 
near the corner; a chain of bundle-sheath cells, 5, surrounding a fibro- vascular 
bundle, x by about 100. 

to the large empty row, the bundle-sheath, are working 
cells ; they contain the green of the leaf, called chlorophyll. 
These green granules require surface positions on the cell 
wall in order to work. The cells have their walls infolded 
to increase the surface to which the chlorophyll granules 



Adaptation to Climate. 



57 



may cling. These cells of the pine are packed very close 
together in pavements one above another throughout the 
length of the leaf, with a slight space between for air, in 




Fxg. 58. 
An evergreen forest. 

order to save space, so precious because it must be protected, 
at such cost to the tree. Figure 58 shows an evergreen 
forest. It and Figure 3 are December pictures ; the one a 
Florida and the other an Indiana landscape. 



LESSON XXXVII. 
Adaptation to Climate. 

Buds. 

It seems to us that buds, as we see them in winter, are 
necessary to trees ; that they are to be expected ; a matter of 



58 



Nature Study. 



course ; so they are in our climate ; the tender, growing points 
of a tree must be protected against the rigors of winter. 
There is no reason for such buds, and there are none, where 
there is little or no change of climate. 




Fig. 59. Fig. 60. Fig. 61. Fig. 62. Fig. 63. 

Fig. 59. Apple buds, five-ranked. Fig. 60. Large, well protected hickory buds. 
Fig. 61. Lilac buds; scales opposite; this is well shown in 61 a. Fig. 62. Buckeye 
buds. Fig. 63. Beech buds. 

Exercise : Gather some large buds from hickory, buckeye 
or horse-chestnuts ; count the scales that protect the living 
parts. Are there hairs in the bud to add to the warmth? 
Is there a varnish or any other means to prevent the bud 



Adaptation to Climate. 59 

from getting wet? Gather walnut, beech, lilac and maple 
buds. What difference is there in arrangement on the stem? 
Is it the same as the leaf -arrangement ? Where are the buds 
of sycamore? Locust? Is there any tree in your vicinity 
that conceals its buds under the bark? Consult the ac- 
companying Figures, 59 to 63. 

An interesting phenomenon one may occasionally see is 
due to latent buds. The early buds of willows are some- 
times killed in spring by frost ; the trees have the power to 
produce branches in this case by means of the latent buds ; 
but considerable time is required to bring them on; so the 
willow's second spring dress comes later than the leafing 
out of the forest trees. It is as if it had resolved not to be 
caught the second time. 

During the winter of 1900-1901, most of the sycamore 
buds were killed by the severe cold; in the spring the few 
buds that had escaped leafed out and after two weeks or 
more latent buds were developed on the other branches and 
the two sets of leaves of different sizes could be distinguished 
until midsummer. 

LESSON XXXVIII. 
Adaptation to Climate. 

The Persimmon Tree. A Special Case. 

Examine carefully several branches on which persimmons 
grow and you will find that they grow on branchlets that 
have grown the same year. This is greatly to their advan- 
tage during winter. Fruit can hardly be killed when it does 
not exist. The winter might be so cold as to kill the tree; 
but if it is not, the branches of the year will grow out and 
put out flower buds and flowers and bear fruit. This is a 
great advantage and would leave the persimmon quite 
ahead in the struggle with frost, only it must take also its 



60 



Nature Study. 



disadvantage, which is that a much longer time is necessary 
in which to mature its fruit, and so it may be caught by 
the frost. 

LESSON XXXIX. 

Adaptation to Climate. 

Influence of the Wind. 

Figure C4 shows a Norway spruce. It grew in an open 
space where light could be had in all directions. It should 




Fig. 64. 

Norway spruce; branches longest on the leeward side. 

have been as symmetrical as the fir in Figure 4 is. Notice 



Adaptation to Climate. 



61 



that the branches are longer on the right hand side. This 
was the northeast side of the tree. To the southwest there 
is an open space of several miles ; prevailing southwest winds 
have thrown the symmetrical light influence out of balance. 
They have lessoned growth on the southwest side and 
increased it on the northeast side. In many countries the 
winds are stronger and they blow much more steadily than 
with us ; in such places exposed trees lean and stretch their 
long limbs in the direction the wind blows in a very striking 




Fig. 65. 

from the seaward, windward side. 



Melbourne. Fla. 



A live-oak forest leaning 
View from the south. 

manner. Figure 65 shows a live-oak forest near Melbourne, 
Florida, every tree of which leans very strongly from the 
ocean, the direction from which the prevailing winds come. 
Figure 66 shows a single oak from the same forest photo- 
graphed from the other side. Neighboring trees made it 
impossible to get the entire tree in the picture. That it 
leans from something is, however, evident. 



62 



Nature Study. 



Exercise: Find twenty-five exposed trees and see if you 
can determine by a study of them that the prevailing winds 




Fig. 66. 

A single oak of the forest shown in Figure 65. 



View from the north. 



have modified their growth ; look in places between forests 
that act somewhat funnel-like in directing the wind. 



LESSON XL. 
The Leaf. 

The Foliage Leaf. 

The most conspicuous thing in the plant world is the green 
leaf, — the foliage leaf, as we call it. A complete foliage leaf 



The Leaf. 63 

lias a blade, a petiole, and stipules. Figure 31 shows all 
these parts; Figures 24 and 25 show the stipules, when 
there is more than one blade, we call the branched leaf com- 
pound, Figures 19 and 25. When these are arranged as in 
Figures 22 and 25 we call the leaf pinnately compound. 
When they are arranged as in Figure 19 we call it palmately 
compound. Figures 20 and 21 show leaves pinnately and 
palmately veined. 

Foliage leaves have many different forms: Figures 12 to 
2 7 show a few of them. It is important for us to consider 
in the presence of every tree, every plant, how its leaves, 
considering form, size, number and arrangement have suc- 
cessfully solved the problem of getting to the light. We 
must learn to consider green leaves as light traps; they 
cannot discharge their most important duty, photosynthe- 
sis, without the light. If we cannot understand this duty 
now, we need not be too much disturbed ; no one fully under- 
stands it. See Lessons XCII and XCIII. It is enough for 
our purposes now to know that no tree can live without, at 
some time of the year, an expanse of green, which in our 
latitude, the lea\^es furnish. 

Exercise: Learn to tell trees by their leaves. Begin 
with the commonest tree in your neighborhood. Collect, 
press, catalogue and draw accurately its leaves. Question 
yourself about the leaf's apex, its base, its margin, its lobes, 
if it has any, and its leaflets, if it is compound. Is its sur- 
face rough? Try the slippery-elm. Is it hairy? Try the 
white poplar. Is it smooth? Is it shining? Is the color 
the same above and below? Try the silver maple. Is it 
petiolate? Has it stipules? Is it thick or thin for a leaf? 
Tough or tender? What comparative advantage or dis- 
advantage has the tree from every quality of its leaves? 



64 



Nature Study. 



LESSON XLI. 

One Duty of Green Leaves. 




Figure 67 shows a fresh, 
green growing end of a 
plant which was cut off 
obliquely and smoothly 
from its stem and thrust 
through a card board into 
a tumbler of water and 
covered with a second dry 
tumbler. The leaves have 
given off water which has 
collected in droplets in the 
upper tumbler. This ac- 
tion of the leaf is called 
transpiration. 

Exercise : Prepare an 
apparatus like this and 
after some two days try to 
form an estimate of the 
amount of moisture given 
off by all the green leaves 
of the great forest, or grass covered plain. You must not 
think any one can do this accurately with data such as this 
experiment alone furnishes, but it is interesting to consider 
to how great a thing our experiment points. The air cannot 
for many reasons be so dry where forests are as it would be 
without them. We must of course, notice that the condi- 
tions of our experiment are not those of a growing plant. 
Our cutting absorbs from water, not from the soil, with its 
varying degrees of moisture; it absorbs through its cut end, 



Fig. 67. 

Leaves giving off moisture. 
Transpiration. 



The Leaf. 



65 



not through roots. The air in the tumbler where the 
moisture is given off soon becomes saturated with moisture, 
which the air surrounding forests and plains rarely is. 
What our experiment shows is the fact of transpiration. 

LESSON XLII. 
The Leaf. 

Leaves in the Role of Spines. 




Fig. 68. 

A barberry spray; leaves become 
thorns. 



Leaves sometimes become 
spines ; we know this because we 
find the spines in the position of 
leaves or of stipules. We know 
it also because we find all de- 
grees of transition from leaves to 
spines. The leaf of the thistle is 
armed with spines. The bar- 
berry bush shows all stages in 
the transition from leaf to spine, 
Figure 68. The locust has a 
pair of spines at the base of its 
leaf in the place of stipules. 
The prickly ash shows a similar 
modification. The English holly 
has spines on its lower leaves ; 
these continue as high up as a 
cow can reach ; above this it has 
no spines. Southey writes of 
this tree: 

'Below, a circling' fence, its leaves are seen : 

Wrinkled and keen, 
No grazing cattle through their prickly round 

Can reach to wound: 
But as they grow where nothing is to fear, 
Smooth and unarm 'd the pointless leaves 
appear." ' - 



66 Nature Study. 

Spines become gradually larger until we at last begin to 
call them thorns ; but size does not determine ; spines do not 
become thorns ; thorns are modified branches. In the same 
way we determine the nature of tendrils, Lesson LI, we can 
tell whether we have thorns or spines in a given case. Do 
they come off with the bark and have they the position of 
leaves ? Then they are leaves. The position of a branch or 
a permanent union with the wood declares them thorns. 

Exercise: Examine haws of all sorts, the honey -locust, 
the prickly ash, and determine whether their sharp append- 
ages are in the positions of leaves or branches ; whether they 
come off with the bark or are a part of the wood of the plant. 

Prickles such as one finds on the raspberries must not be 
confounded with leaf -spines. They are emergencies in the 
nature of highly complex and hardened hairs. 



LESSON XLIII. 
The Leaf. 

Leaves in the Role of Bracts. 

Notice the leaves of mullein, Figure 54. It will be seen 
that they decrease in size from below upward. They finally 
become so small that the photograph does not show them. 
They are mingled among the flowers all the way to the top 
of the stalk. These reduced leaves we call bracts. They 
surround dandelions and can be seen reflexed in Figure 88. 
A whorl of four surrounds a group of dogwood blossoms. In 
this case they are very showy to attract insects. A beauti- 
ful blossom in early spring, the liverleaf that grows from a 
bunch of last year's three-lobed leaves has a whorl of three 
green bracts so close to the flower we call them sepals some- 



The Leaf. 67 

times ; the only harm that comes from this is, it confuses us 
if we are hunting in a key for the name of the plant. No 
one can tell every time where bracts leave off and sepals 
begin ; no more can he tell where leaves stop and bracts 
begin. 

We will have accomplished the purpose of this lesson 
when we see by a study from plants themselves that bracts 
are only reduced leaves. 

Exercise: Begin with the daisies and find as many 
flowers as you can that are surrounded by one or more 
whorls of reduced leaves. What is the chaff of oats, wheat, 
rye, barley, timothy hay and other grasses? See if they are 
not bracts, little leaves in among the flowers. 



LESSON XLIV. 
The Leaf. 

Leaves in the Role of Sepals and Petals. 

When a whorl of bracts, — reduced leaves, grows very 
close to the flower we change its name and call it a calyx ; 
and instead of bracts for the separate parts, we say sepals ; 
sometimes the sepals are green ; often they are white, yellow, 
etc., and give its color to the flower, in part, just as the 
bracts themselves are colored white sometimes, as in dog- 
wood. They are sometimes as small as the separate hairs 
of the dandelion's down ; again they are larger than ordinary 
leaves as in the lily. Position alone determines whether or 
not they are sepals. Many flowers have just two whorls of 
floral leaves, Figure 40; in this case we call the outside 
whorl a calyx and the inside whorl a corolla. The separate 



68 Nature Study. 

leaves 1 of the corolla are called petals. The sepals and 
petals of flowers exist under many disguises ; they are grown 
together sometimes. One is entirely suppressed sometimes, 
in which case we call the one that is left the calyx; the 
petals often grow on the sepals ; sometimes the petals are 
very unlike as in the bean, Figure 46, the snapdragon, and 
many other flowers ; so are the sepals. You will often have 
difficulty in determining which are sepals and which petals. 
Do not become discouraged at this ; experts have difficulty ; 
if you are interested in the naming of flowers you are ready 
for a work on systematic botany. Gray's Manual is a very 
good one. Details that would guide you in every case are 
too numerous for a book like this to give them. 

The purpose of this lesson is to point out that sepals and 
petals whatever their shapes or disguises, are modified 
leaves. If it seems to you that it is impossible that organs 
like the spurs of many flowers can be leaves, two things will 
help you: Study spurs in all sorts of spurred and irregular 
flowers and see if you cannot arrange a list in which they 
become simpler and simpler until they fade out; study a 
very complex flower in younger and younger stages until 
they are so small you require a lens to see them; are the 
flowers more regular as they become younger? Are the 
petals and sepals more alike? We apply this term irregular 
to flowers that do not have all the separate parts of the 
same whorl alike. 



The Leaf. 



69 



LESSON XLV 



The Leaf. 



Leaves in the Role of Stamens. 




Fig. 69. 

The water-lily's petals become 
stamens. After Gray. 



We need in this lesson to 
know what a stamen is. Fig- 
ure 69 shows a complete sta- 
men at the right: its stem, its 
lower part, is called the fila- 
ment ; the enlarged upper part 
is the anther ; the anther bears 
the pollen; see Lessons XVII 
and XX. Is the stamen a 
modified leaf? Students where water-lilies are to be had 
are especially fortunate for this lesson. Go to the water- 
lily and see if you do not find something like Figure 69. 
Here is a gradual transition from a perfect stamen, right 
hand figure to a perfect petal, left hand figure. Other 
flowers will show the same thing. I have often seen it in 
roses. Examine the peony and you will certainly find it. 
Exercise: Look at the ends of the innermost petals of 
roses for anthers on their tips. Gather some wild roses ;try 
to estimate the number of their stamens; compare them 
with cultivated roses; have the wild rose stamens become 
petals under cultivation ? Cultivation (plenty of rich plant 
food of the right quality) changes the stamens of many 
flowers into petals. This is another reason why we think 
stamens are modified petals. It must not be concluded 
that in the cultivated flower there is a petal for every stamen 
in the wild state and no more. 



70 



Nature Study. 



Fig. 70. 
A foliage leaf functions as a pitcher 
and tendril, a. An East Indian leaf; b, 



LESSON XLVI. 
The Leaf. 

Leaves in the Role of Pistils. 



We have seen, Lesson 43, 
that leaves gradually 
change on the same flower 
stalk into bracts ; and that 
bracts as insensibly become 
sepals; sepals in turn be- 
come petals which again 
may become stamens. We 
have also seen that leaves 
become spines sometimes 
and we shall see in Lesson 
LI that they become ten- 
drils. In the pitcher-plant 
Figure 70. In a curious plant in 




ordinary pitcher-plant leaf. 

they become pitchers 
North Carolina leaves become traps in which flies are caught. 
In many plants leaves become scales. All these organs: 
prickles, tendrils, stamens, pitchers, scales, and the highly 
specialized foliage leaf itself, are doubtless end results in 
the transformations of a common leaf -like form. Spines 
would have to go back to or toward this primitive structure 
before they could become tendrils or stamens. For the 
same reason stamens do not generally become pistils ; they 
would need to go back in most cases and set out on the new 
road which ends in pistils. This is what we should expect, 
and it is what we generally find. 

Exercise: Look on double flowers of all sorts for pistils 
at the center and see if in many instances they have not 
become petal-like or even in extreme cases, green leaves 
again. Find some if you can that are rolled somewhat pis- 
til fashion and with a "style-like apex." Do not be in a 



The Leaf. 71 

hurry to reach this or any other conclusion to which your 
books point. Look often and long and let conclusions grow. 
Examine the petalloid stigmas of the common blue flag. 

LESSON XLVII. 
The Leaf. 

Leaves in the Role of Bud-Scales. 

It will be useful to study this lesson in the spring when 
the dogwood begins to grow. You will find that growth 
from below pushes the scales up and four large petaloid 
leaves take the place of the scales of the flower bud. These 
were described in Lesson XLIII, and called bracts; the 
dogwood thus furnishes us evidence that bracts and scales 
are alike modified leaves — the scale in this instance is the 
tip of the leafblade ; it cannot grow and its death produces a 
notch in the apex of the dogwood's bracts. It clings on 
for a while, brown, while the bract is white or greenish 
white. 

It is sometimes the stipules of the leaves that form the 
bud-scales. This can be well seen in the forming of new 
buds of the magnolia in the fall. It again happens that the 
bud-scale is the petiole of the leaf. If a sweet buckeye can 
be found, its bud-scales will show that they are reduced and 
modified petioles because some of them will be tipped with 
the remains of the leaflets of its palmately compound leaves. 
Another reason why we think bud-scales are modified 
leaves, is, the scales are arranged on the buds in the same 
order that the leaves are on the stem. Consult Lessons 
XV and XVI on leaf -arrangement. 

Exercise : First learn Lesson XVI thoroughly so you can 
quite understand the two-fifths arrangement ; next examine 
the arrangement of the petals on a rose or apple blossom 
and see if it is not the same ; now examine the arrangement 



72 Nature Study. 

of the scales on rose or apple buds and you will find that the 
arrangement is the same. 

Exercise II: Watch the formation of beech and tulip 
buds and their openings in the spring and see if you can find 
any reason why their scales are stipules. 

Exercise III: Watch the unfolding of lilac buds in early 
spring and you will see every stage of transition from scale 
to leaf. See if you can tell by the veining of a lilac bud- 
scale that it is a modified leaf -blade. Note especially the 
arrangement of leaves on lilac ; the leaves are opposite and 
successive pairs are at right angles to each other. Notice 
now the arrangement of the bud-scales ; is it the same ? See 
Figure 61 a. 

Exercise IV: Examine a spray of arbor-vitae. Its 
leaves are reduced o small green scales closely appressed to 
the stem; see if there are not two kinds, one on the side and 
one on the edge of the flat branch. Examine also a spray 
of cedar for leaves reduced to scales. What are the bud- 
scales of the Norway maple? 

LESSON XLVIII. 
The Leaf. 

Leaves in the Role of Bulb-Scales. 

A white lily bulb will serve us best for this study. Figure 
7 1 shows one taken up in November, — a good time to study 
this lesson; any time in Autmn will, however, do. The 
scales at the bottom are the bases of leaves in which food 
has been stored up to help in making stem, flowers and 
seeds the corning year. The leaves which are still green at 
the top and still function as foliage leaves, are pale and 
thickened at their bases and function as storehouses of food, 
— a function of leaves not hitherto noted. Probably there 
is no leaf that does not in some part and at some time, hold 
some stored food. 



The Leaf. 73 

Exercise: Cut across an onion; does each of the several 
concentric circles you see represent the base of a leaf in 




Fig. 71. 

A lily bulb; leaves as storehouses for food. 



which food is stored? Go for answer to the young growing 
onion and see if you can trace its leaves to circles in its bulbs. 



74 



Nature Study. 



LESSON XLIX. 



The Leaf. 



The Pappus of the Dandelion. 




Fig. 72. 

A dandelion flower. 1, calyx; 2, 
stamens; 4, pistil. After Gray. 



corolla , 3 , 



Exercise: Get a 
dandelion that has 
just fully bloomed ; 
cut the large head 
in two from above 
downward so as to 
split the stem on 
which it grows. 
Look at the cut 
half of the large 
head and see if it 
is not composed of separate flowers, many of which look like 
Figure 72. Compare this part by part with the simple 
flower in Figure 40 and with the separate parts of a spring- 
beauty. You will see the same number of separate whorls 
in them; sepals, petals, stamens, pistils. Similar parts are 
similarly named in the two figures. The outside member of 
the dandelion flower is very unlike that of Figure 45, and 
of flowers generally, but we have already learned that 
position determines ; form cannot, for forms are as different 
almost as different kinds of flowers. This dandelion down, 
then, is a modified calyx. But as we have already learned 
that a calyx is a whorl of modified leaves we are, therefore, 
justified in concluding that the dcwn which we find on the 
dandelion seed and which occurs with modifications on 
many kinds of blossoms is an extreme modification of leaves. 



The Leaf. 



75 



LESSON L. 



The Leaf. 



The Blossom End of the Apple. 

What are the dead brown appendages at the blossom end 
of the apple ? They seem to be leaf -like ; perhaps they are 
the tip of the calyx. 

Exercise: When the apple blooms next, examine the 
blossom carefully. The parts of the apple are present in 
the blossom. Some parts of the blossom are dropped, 
some remain and grow greatly. Mark one definite apple 
blossom and watch it every day until it becomes a small 
apple and you cannot help learning that the calyx closes in 
about the pistil and at last fuses with it and then both 
thicken together. As the calyx consists of modified 
leaves and the pistils of modified leaves it must be that the 
edible portion of an apple consists of modified leaves. 
You can watch the modification all the way from the leaf 
to the apple. 

Cut an apple across midway 
between stem and blossom and 
scrape a little from next to the 
core ; now scrape a little from 
next the peeling ; which is softer 
and tenderer? See if you can 
tell by any appearance where 
the outside and inside meet, 
compare your cut apple with 
Figure 73. The leaves that 
went to make the apple's pistil 
were wrapped with the upper 
side in and when the leaves of 
the calyx were bent together their upper sides were also in. 




Fig. 73. 

A cross-section of apple 
by Miss Helen M. Fiske. 



Drawn 



76 



Nature Study. 



In eating the apple then you eat the upper side of the calyx 
leaves and the under side of the pistil leaves. Notice care- 
fully this figure (Fig. 74) of the upper and under side of a 
leaf and see what difference the two sides present. The 
upper side at least makes apple pupl that is firmer than the 
under. The upper side of the leaf is the compact side ; the 
lower is the spongy side. 

Exercise: Pull some raspberries and blackberries your- 
self. Does a portion of the top of the flower stem come off 
with the blackberry that stays on with the raspberry? 
When we eat a blackberry we are eating a part of the stem 
that has become fleshy. Examine the seeds of the black- 




A section of a leaf. 



Fig. 74. 

The lower side is spongy. After Gray. 



berry and see if the separate seeds are not made on the plan 
of a cherry, a stone within and the fleshy part without. 
The cherry has no bloom on it when ripe as the apple has; 
it is the ripened pistil alone. This pistil leaf has greatly 
thickened; the outside which is the under side of the leaf 
has become fleshy and the inside which was the upper side 
of the leaf has become the hard stone. 

Exercise IV: Study walnuts, strawberries and pears 
from the first appearance of the flowers until they are fully 
formed and see what their several fleshy parts are. Try to 



The Leaf. 77 

learn what parts of the stem or flower has become the edible 
portion of every fruit you eat. 



LESSON LI. 

Leaves in the Role of Tendrils. 

Figure 24 shows us a greenbriar leaf. Its stipules have 
abandoned the office of foliage leaves and are entirely given 
up to support ; they appear as tendrils. Sometimes tendrils 
are modified branches. If they grow out from the wood so 
as not to strip off with the bark they are modified branches 
instead of leaves. Compare the distinctions between 
prickles and thorns, Lesson XLII. 

Exercise: Find out by this 'rule what tendrils are in 
grapevines. 

Figure 75 is a leaf of a garden- 
pea; notice that in this case the 
leaflets of its compound leaf are, 
several of them, converted into 
tendrils and that its stipules have 
grown to the size of leaves to dis- 
charge the duties of the green leaf, 
which the leaflets have laid down 
in order to support the plant. Ex- 
amine the sweet pea plant care- 
Fig. 75. fully. It has given up its leaflets 
Ba^es^ I pi?nt e Life eaf ' FrCm for tendrils also, but instead of 
enlarged stipules for leaf surface, it has expanded append- 
ages along its stem; Figure 76. 




78 



Nature Study. 




Fig. 76. 

A sweet pea leaf. Drawn from 
nature by Miss Helen M. Fiske. 



Another way to tell whether a 
tendril is a modified branch or 
leaf is by its position. Remem- 
ber a branch generally grows 
from a bud in the axil of a 
leaf, — that is, from the stem 
just above the leaf. Figure 77 
shows a tendril of passion flower 
in this position. It is, therefore, 
a branch, not a leaf. 

Exercise : Find some tendril- 
bearing plant not here mer- 
tioned and ascertain by one or 
the other, or both, of the above 
rules, whether its tendrils are 



modified leaves or branches. 



LESSON LII. 



How Tendrils Behave. 



Exercise: Find some tendril-bearing plant and note in 
what direction some tendril points that is nearly grown, but 
has not yet begun to twine itself about an object. Watch it 
every ten minutes for a few hours ; does it move around in a 
circle or an ellipse? What can it be doing? Is it hunting 
for something about which to twine ? Let the tendril itself 
answer; bend a twig over so it will just lightly touch the 
tendril near its tip and see if it does not stop its movement 
in a circle and begin to twine about the twig. How long is 
it before the tendril has taken strong hold on its support? 




How the Bean Finds its Pole. 79 

Examine several 
tendrils that have 
taken fast hold on 
some object and see if 
Figure 78 represents 
them correctly. What 
are the coils between 
the plant and its sup- 
port for? Let the 
tendril again answer; 
watch its action in a 
storm and see if the 
purpose of this can 
Fi s- 78 - be to yield somewhat 

A tendril coiled between plant and support. 
To pull the plant nearer to the support? To to the pull OI the 
enable it to yield a little in the storm? After 

Gray. leaves so that it may 

not be suddenly snap- 
ped off. May it also 
be to pull the plant and support closer together? 



LESSON LIII. 

How the Bean Finds its Pole. 

Plant twenty or more twining beans, corn-field beans. 
As soon as they come up put poles down for them to climb, 
some five inches away and on all sides of the beans. Watch 
the beans as they grow and see if they grow up and reach 
out in some direction as if hunting something. Mark the 
direction in which they point from hour to hour and see if 
they swing round in a circle in search of their pole. Do they 
grow a little longer and reach a little further every round? 
When they have almost reached the pole at a distance of 
several inches remove it and see how far the beans can 
reach. Of course the same experiment can be tried with 



80 Nature Study. 

morning-glories or any other sort of twining plant ; it would 
be very profitable to try it with several twiners for compara- 
tive study. These experiments could be tried on the farm 
or in the garden in spring at very little cost of time. Let 
the results grow with the season. If the bean fails to find 
a pole within supporting distance, does it hend to the 
ground, establish a new base and begin to hunt in its new 
territory as before? 



LESSON LIV. 

The Multitude of Plants. The Struggle for Existence. 

Count the grains on what you think is an average ear of 
corn. I have just found 400 well developed grains on a 
single ear. This means that one grain can become 400^ in 
one year and this 400 can become 400x400 or 160,000 the 
second year; and these 160,000x400 or 64,000,000 the third 
year; 25,600,000,000 the fourth year. One bushel will 
yield as many bushels as one grain will grains ; so one bushel 
will yield 25,600,000,000 bushels in four years. 

The earth's land surface is 52,500,000 square miles. One 
bushel will plant eight acres and eighty bushels will plant 
640 acres, or a square mile and to plant the whole earth 
would require 52,500,000x80, or 4,200,000,000 bushels. 
One bushel of corn would yield enough corn in four years 
to plant the whole earth more than six times over. 

Read the chapter, 'The Crowd of Animals," in Jordan 
and Kellogg's ' c Animal Life." 

Exercise : Estimate the number of beechnuts on a beech 
tree and allowing that each tree will begin to bear at thirty 
years old and bear at the same rate, how long would it 
require for the descendants of one tree to occupy the entire 
United States allowing 1,000 square feet to each tree? 
Read Chapter III, of Darwin's "Origin of Species." Natur- 



The Multitude oj Plants. 81 

alists are agreed that every living species, if its food did not 
fail and it had no casualties from climate or enemies, could 
in a short time occupy all the available space. This fact 
makes the struggle for existence inevitable. 

Count the seeds of several plants and the eggs of several 
different birds and insects and calculate their rate of in- 
crease and see if you cannot verify this conclusion. In this 
struggle for existence between plants, every slight help, 
every noticeable adaptation is important. A plant that 
has some advantages in the scattering of its seeds might 
win in this struggle, while other plants without these ad- 
vantages, however slight they may seem, might fail. We 
are now to study several ways by which seed dispersal is 
brought to pass. The, student should not forget while 
working out these lessons that he is dealing with one of the 
means by which the plant in question has successfully held 
its own through the ages in the midst of a multitude of 
plants that would have crowded it out if they could ; in the 
midst of many animals that have lived off of it in part at 
least, and in the midst of forces, — heat, light, moisture, 
soil, gravity, etc., that have never been considerate of it in 
any way. 

All the preceding lessons on adaptation to the light, and 
all the succeeding lessons on various topics may be profit- 
ably considered with reference to the struggle for existence. 
Indeed, whatever the book or lesson, if it concerns itself with 
any plant or animal it cannot help aiding you in your study 
to remember: this species has existed on the earth through 
its ancestors from the beginning. What qualities, what 
adaptations does it possess that have aided in this long and 
successful struggle ? No one can fully answer this question 
nor [does any one know all the conditions that might help 
to the answer. The question is not suggested because it is 
easy, but because it is important. Because men are work- 



82 Nature Study. 

ing on it and because it will help any one to interpret what 
he sees. 

LESSON LV. 

Seed Dispersal. 

The Wind. Winged Seeds. 
Figure 79 shows the fruit 




of the linden, often called 
linn. This is found hang- 
ing on the tree from August 
to December. 

Gather the fruit when it 
; is ripe and compare it with 
the figure. Drop it from a 
height when the wind is 
blowing and when there is 
no wind. Why does it 
whirl as it falls? Notice 
i that the leaf-like bract 
clings to the peduncle for 
half its length and then 
leaves it at an oblique 

J angle. Put it down and 

Fi 79 see whether it lies flat on 

Wing-like bract of linden seed. the ground. Does it lie 

m such a manner that the wind can easily get under it to 
pick it up and carry it further? 

Gather in the autumn a quart of the seed of sugar-maple. 
When the wind is blowing, let a boy who volunteers to do 
so, sow a hand full from the top of the house. Every one 
who sees will be surprised and pleased. Go to the east side, 
the leeward side of a maple forest late in the fall and see the 
sowing of young maples the wind has effected a quarter of 
a mile or more from the trees. 



Seed Dispersal. 
LESSON LVI. 



83 



Seed Dispersal. 

Other Seeds with Wings. 

Exercise: Gather as many as you can of the following 
tree seeds: ash, hop-tree, Ailanthus, (tree of heaven), water- 
beech, ironwood, Catalpa and pine. The pine seeds will be 
found in the space just above the spreading scales of the 






Fig. 80. Fig. 81. Fig. 82. Fig. 83. 

Fig. 84. Fig. 85. Fig. 86. 

Fig. 80. Winged seed of water-beech. Fig. 81. Winged seed^of pine. Fig. 82. 
Winged seed of ash. Fig. 83. Winged seed of tulip. Fig. 84. Winged seed of 
maple. Fig. 85. Winged seed of ironwood. Fig. 86. Winged seed of hop-tree. 
Drawn from nature by Miss Helen M. Fiske. 



two-year-old pine cones. The Catalpa seeds will have to 
be taken out of their long bean-like pods. All these seeds 
may be gathered in autumn. The seeds of the elm may be 
added to this list if they are gathered in the early summer 



84 Nature Study. 

Compare your seeds with Figures 80 to 86. Describe them 
in words or sketch them or write out a description of all of 
them, giving special attention to the differences between 
them. What trees or plants do you know by their seeds? 
Increase this number all you can and you will be doing very 
valuable nature study. 

When these seeds dry, do they warp in such a manner as 
not to lie flat on the ground? How does this help them? 
In North Carolina a pine forest will very soon thickly cover 
an abandoned field. How do the seeds get there? Read 
Thoreau's essay, "The Succession of Forest Trees," in 
"Excursions." 



LESSON LVII. 
Seed Dispersal. 

The Dandelion's Parachute. 

Figure 87 shows many dandelions bearing seeds. Each 
seed is provided with a parachute to carry it to some distant 
home. You must consult Figure 89 with dandelion seeds in 
your hands. How high is the stem that carries these seeds? 
Measure it and see if it is not a foot or more. You have 
played with these hollow stems many times, making them 
into fantastic curls. What are these long stems for? The 
dandelion flower bloomed right on the ground, did it not? 
The flower was very heavy; it would have taken a much 
stronger stem to hold it up than the dandelion has ; besides 
the flower is much safer on the ground than it would be a 
foot above it, and it can do its work just as well close to the 
ground. But the seeds to be well scattered must be given 
to the wind above the grass in which the dandelion grows so 
that it may not catch and entangle them close to the home 
blossom, so also that the wind can the better get hold of 
them. We need not go away from home for wonders ; there is. 



Seed Dispersal. 



85 



not in all the earth a creature more wisely cared for than 
the dandelion that grows at every door. 




Dandelions in fruit 



Fig. 87. 
Photographed by Prof. J. F. Thompson 



"O'er land and sea I traveled wide, 
My thought the world could scan, 

But wearily I turned and cried 
Oh little world of man. 

"I wandered by a green woodside 

The distance of a rod, 
My eyes were opened and I cried 

Oh mighty world of God." 



Exercise: Mark a dandelion as soon as it blossoms so 
that you cannot mistake it for another. Watch it every 



86 




Fig. 88. Dandelion plant. 
M. Fiske. 



Fig. 88. Fig. 89. 

Fig. 89. Dandelion seed. Drawn by Miss Helen 



few hours night and day, and see how quickly when the 
right time conies, it shoots up and sends its seeds on their' 
dandelion mission. 



Seed Dispersal. 



87 



LESSON LVIII. 
Seed Dispersal. 

Other Pap pus -Bearing Seeds. 

Figure 92 is a seed of a thistle; figure 93 of irorrweed; 
Figure 90 of clematis; Figure 91 of milkweed. Compare 
them all with the seeds themselves. Find all the seeds you 
can that have some kind of hairy arrangement to make them 




Fig. 90. Fig. 91. Fig. 92. Fig. 93. 

Fig. 90. Clematis seed. Fig. 91. Milkweed seed. Fig. 92. Thistle seed. Fig 
93. Ironweed seed. Drawn by Miss Helen M. Fiske. 



light enough for the wind to carry them. Make collections 
of these seeds for your home or school in small covered 
glasses, jelly glasses will do, all correctly labeled with the 
time and place of gathering them and if vou know it, the 
time of blossoming. 



88 Nature Study. 

LESSON LIX. 
Seed Dispersal. 

Some Adaptations of the Thistle. 

The thistle has no friends in the world; it has taken care 
of itself for so long that it does not expect anything else ; it 
will be worth while for us to find out how it does this. 

Do not try this lesson without thistle seeds that you have 
gathered for yourself. Notice how very small the seeds are. 
Collect enough seeds of thistle to weigh a grain. Get your 
druggist to weigh them for you; break them off from the 
hairy balloon before weighing. Do not think that it makes 
no difference how small the seeds are; this is one of the 
thistle's important secrets of success in the world. If the 
seeds were larger they could not be sent so far even in its 
matchless balloon. You must not think that for thistles or 
men there is an advantage without a disadvantage. This 
small seed contains all that the thistle that is to be, heirs 
from its parent thistle. It will take it a long time to get a 
start. Go again to the pasture where you gathered the 
seeds and you will see thistle rosettes flat on the ground; 
they are one-year-old thistles. They have to work a year 
to make up for the small start they had in the world. 
Consult Lesson XII on mullein. They are storing food so 
they will be able to grow a stalk and bear seeds next year. 

Every one knows the thistle is armed with prickles ; these 
serve to defend it through the two whole years it requires 
for maturing its seed. 

Exercise: Find in summer the smallest thistle you can. 
Mark it so you can't mistake it and watch its growth from 
time to time till it bears seeds the following year. 



Seed Dispersal. 



89 



To learn what its balloon is, see Lesson XLIX. 
Read Burns's poem, "The Daisy." 

"The flaunting flowers our gardens yield 
High sheltering woods and wa's maun shield ; 
But thou beneath the random bield 

O' clod or stane, 
Adorns the histie stibble field 

Unseen, alane." 



LESSON LX. 
Seed Dispersal. 

Smallness of Seeds and Spores. 

As we saw in the last lesson, smallness of seeds has its 
advantages. The seed of corn is much larger than that of 
the thistle. How much larger? "Would you rather I would 
tell you or would you prefer to balance them on as delicate 
a balance as you can get and find out for yourself? 

Because of this good start the corn has in the world, it can 
be planted in May and it will ma- 
ture in early autumn. We sow 
4p oats in April and harvest it in July. 
0j& Because smallness or largeness of 
seed has each its advantage, plants 
have carried both to remarkable 
extremes. 

The fern gains in smallness by 
not producing seeds at all, but 
spores, which grow in spore cups 
collected into little fruit-dots gen- 
erally on the under side of the leaf. 
These fern-spores are so small one 
can only see them with a micro- 
scope. They float in the air as a 
part of its impalpable dust. They 
Fig. 94. often light on the perpendicular, 

Fern rootstock with fertile 1 1 11 r tt 

and sterile fronds. After Gray, damp, rOCK Wall 01 a gorge. Here 




90 



Nature Study. 



they grow into small, kidney -shaped bodies, quite unlike 
ferns. These bodies bear on the under side rootlets, which 
enable them to cling to the rock, and male and female cells 
which unite and form embryos. Fern seeds then are not 
carried to this apparently inhospitable home, but young 
ferns are formed there by a minute cell of the fern, which it 
sends out by the wind for this purpose. The fertilized cell 
grows at once, and so has no need of seed coats for its pro- 
tection. 







Fig. 95. Fig. 96. 

Fig. 97. Fig. 98. Fig. 99. 

Fig. 95. Fruit-dots of Figure 94. After Gray. Fig. 96. Cross-section of a 
fruit-dot of Figure 94. Fig. 97. Sporangium of Figure 94. After Gray. Fig. 98. 
Prothallium bearing archegonia, antheridia and rootlets. After Gray. Fig. 99. 
A young fern plant. After Gray. 

Exercise: If you cannot learn all this lesson now, you 
can see the fruit-dots on the under side of the fern leaf, Fig- 
ures 95 and 100. You can visit the greenhouses and see 



Seed Dispersal. 



91 




Fig. 100. 

Section of fruit-dot and indusium of maiden-hair-fern, x by about 100. 

young ferns, prothallia, they are called, the word is plural, 
its singular is pro thallium, Figure 98 ; and sometime you can 
see through the microscope the sporangium, Figure 97, and 
the spores it contains. You can learn also from this lesson 
that when you see a plant able to live so extraordinary a 
life as the fern does on a rock, it is in some way specially 
fitted to its kind of life. 

LESSON LXI. 
Seed Dispersal. 

The Spanish Xeedle. 

We have seen that seeds are variously winged and are 
scattered by the wind, Lessons LV and LVI, that they are 
borne up by buoyant, hair-like appendages, by means of 
which the wind carries them. Lessons LVII and LVIII. 



92 



Nature Study. 



Sometimes they cling by special contrivances with which 
they are provided, to men or animals, and are carried long 
distances. The common Spanish needle is one of these, 
Figure 101. Notice that the barbs extend away from the 
point of the needle, fish-hook-like; they go in easily, but 
come out with difficulty. Can any instrument be more 
nicely adapted to carry out its purpose than these Spanish 




Fig. 101. Fig. 102. Fig. 103. Fig. 104. 

Fig. 101. Spanish needle. Fig. 102. Cockle-bur. Fig. 103. Burdock-bur. Fig. 
104. Chestnut-bur. Drawn from nature by Miss Fiske. 

needle points? How came this weed to be thus provided 
for? When you have really seen into a case of fitness like 
this, you have as much right as any one to ask this question ; 
You had better answer it wrong than not to try to answer 
it at all. 

Exercise: Collect as many kinds of Spanish needles as 
you can. Are these barbed bristle-points in or out as the 
seed grows on the stem? How should they be, considering 
the interests of the Spanish needle? Do Spanish needles 
sink or swim in water? How long will they swim? Do 
they have a seed coat that keeps them from becoming soaked 
for a considerable time in water? Do they grow in great 
abundance in corn fields that are often overflowedby streams? 



Seed Dispersal. 93 

LESSON LXII. 
Seed Dispersal. 

Other Seeds that Cling. 

Collect cockle-burs, Figure 102, burdock-burs, Figure 103, 
sticktights, chestnut burs, Figure 104, bed-straw seeds and 
as many other prickly seeds and burs as you can. You can 
get a pocket lens that will magnify five or ten diameters 
from the Bausch and Lomb Optical Co., Rochester, N. Y., 
that will greatly help you. Talk over with one another the 
differences between these seeds and their adaptations for 
sticking. Cockle-burs are very abundant along streams in 
my neighborhood, where they overflow their banks ; are they 
in yours? Answer all the questions for cockle-burs that are 
given for Spanish needles in Lesson LXI, especially the 
question, how many days will it swim? How long will it 
float in a water current and how far will the current of your 
swollen stream carry it in this time? 

LESSON LXIII. 
Seed Dispersal. 

Currents of Water. 

It is intimated in Lessons LXI and LXII that Spanish 
needles and cockle-burs are distributed by currents of water 
as well as by clinging to men and animals. Go along your 
nearest stream and get acquainted with as many plants as 
you can that grow abundantly and mainly, or altogether 
there; do not be discouraged if you cannot name them all, 
onlv be sure that you know them. You will be almost sure 
to find the great ragweed. 

Exercise: In October gather a quantity of the seeds of 
the great ragweed or some other river plant bearing smooth 
seeds. Will these seeds float? How long will they float? 
How fast does vour stream flow in time of flood and how 



94 Nature Study. 

far could these seeds be carried before they will sink? When 
the seeds have floated as long as they will, will they still 
grow if you dry them and plant them? If you try these 
things yourselves, you will not need to be told that currents 
of water plant seeds in very distant soils. Suppose a new 
made island is one hundred miles from land. In how many 
ways that you can think of could seeds get there? Could 
birds carry them in mud that clings to their feet? Read 
''Occasional Means of Distribution" in Chapter XII of the 
"Origin of Species." 

LESSON LXIV. 
Seed Dispersal. 

Fruit. The Service of Animals that Eat it. 

Crows assemble together sometimes to the number of 
200,000 or more and roost through the winter in the same 
trees; such a place is called a crow-roost. There is a crow- 
roost in Arlington Cemetery near Washington, D. C. In 
1889 Mr. Walter B. Barrows collected all the droppings of 
the crows from two square feet, and in this material he 
found 4,764 seeds of plants brought there by the crows. He 
estimates that on the ground of the entrie roost there were 
700,000,000 seeds ; enough to sow a thousand acres as thickly 
as wheat is sown. These were the seeds of stone-fruits, like 
cherries, sourgum, sumac, etc. The birds had eaten them 
for the fleshy part. The stones had prevented the seed 
from being destroyed by the digestive process. 

In many parts of our country the mistletoe is found. 
It grows on branches of oak, elm and other trees many feet 
from the ground. It could not spread if its seed were not 
sown in these inaccessible places in some way. The seeds 
are gummy and cling to the bills of the birds that are eating 
them. The birds then fly away, wipe their bills on the 



Seed Dispersal. 95 

limbs of distant trees and so plant the seeds where they can 
grow Figure 135 shows a section of an oak branch through 
its own wood and that of the mistletoe growing on it. How 
are the seeds of raspberries, blackberries, mulberries, wild 
cherries, Virginia creepers, etc., dispersed? Next time you 
see a bird eating a cherry don't hurry to throw at it ; think 
of this vast and mutually beneficent relationship between 
plants and birds. The plants feed the birds and the birds 
plant the seeds for new plants. Is it not a wise, fair arrange- 
ment? Consult Lessons XXV and LXV. 

-LESSON LXV. 
Seed Dispersal. 

Nuts and Animals. 

Have you noticed that walnut trees often grow along 
fence rows? They are planted there by some animals, es- 
pecially the squirrel; but as he, for some reason, never 
returned to claim his hoarded treasure, it has grown into a 
tree. 

Exercise : What birds or mammals feed on acorns, beech- 
nuts, hickory -nuts, chestnuts or hazelnuts? What birds or 
other animals hoard them for winter use ? All these birds or 
other animals sometimes bury or drop them at distances 
greater or less from the tree that bore them. Here is our 
wise arrangement again ; it is wiser than we think. It is not 
artificial. Both parties are vitally interested in maintain- 
ing it. In Thoreau's essay, "The Succession of Forest 
Trees," referred to above. Lesson LVI, he shows that in a 
neighborhood of oaks and pines, if the pine forest is cut 
down, an oak forest will take its place because squirrels, 
birds, etc., will carry acorns to the site of the original pinery. 
If the oaks are cut down the wind will sow pine seeds where 
the oaks had been. Thoreau credits Linnaeus with saying, 
"While the swine is rooting for acorns he is planting acorns." 



96 



Nature Study. 



LESSON LXVI. 
Seed and Spore Dispersal. 

Special Contrivances. 
Everyone must know that if you touch one of the ripe 
seedpods of a touch-me-not, it bursts with a suddenness and 




JJ* 



0:~~-~" 



s~b*=g~~ 









<5- ° OW^ 




^ o^"^ 



Fig. 105. 

Fern spore-case discharging spores. After Atkinson. 



force that send the seeds to considerable distances. The 
seed-pods of some other plants do the same thing — as, for 
instance, the fireweed, which thus gives its sail-provided 
seeds to the breeze. 

Spores are sometimes scattered by similar means. 

Figure 105 shows a sporangium of fern, greatly magnified. 



Spore Dispersal. 



97 



It will be seen that at the left side in the figure, the cells 
change in character; here the adhesion is less than other- 
wheres in the outer circle ; the contrivance bursts here ; when 
the cells of the outer ring dry out, their walls tend to collapse 
and the outer walls being thinnest, give way and a united 
pull is exerted ; suddenly the spore-case bursts and scatters 
the spores to the wind. 

Exercise : Get some stable 
manure and put it on wet 
blotting paper under a bell- 
glass. This compost con- 
tains spores of a white mould 
that will cover it all over in 
two or three days. Gener- 
ally after this dies, in about 
nine days after the prepara- 
tion is set, a mould of smaller 
growth comes up, Figure 
106. The black cap at the 
top is filled with thousands 
of spores too small to be seen 
with the naked eye. When 
the spores are ripe, the en- 
larged portion of the stem 
swells out and pulls the part 
in the spore cap out forcibly 
and suddenly, sending the 
cap two feet or more into the 
air. The spores are caught 

by the wind and scattered 
Fig. 106. Fig. 107. ^ er the s Stock eat 

Fig. 106. Pilobohis crystallinus, a ° 

mould that has no common name. See them and theV paSS through 
text. Drawn by Miss Fiske. Fig. 107. . . . . ° 

Pilobolus shooting its spore-case into the their digestive Organs Wlth- 
air and scattering spores. Drawn by 

Miss Helen m. Fiske. out damage and if they have 

w^arm, wet weather for a few days they grow and ripen again 




98 Nature Study. 

in the droppings of the stock. Everything about their 
growth can be seen under a bell-glass, except the spores, 
which require a microscope. They will shoot off their little 
cannons, hundreds of them and cover the interior of the 
bell-glass with their little black caps. Get a high bell-glass 
if you can and see how high they can shoot. A curious 
thing about the shooting is, the caps always turn over, as 
shown in Figure 107, and land on the bell-glass spore-side up. 
When this shooting occurs in the open air the caps, on ac- 
count of their heavier specific gravity, fall away from the 
spores and leave them to be scattered by the wind. 



LESSON LXVII. 
Seed Dispersal. 

Special Contrivances. 

A walnut is round and can roll long distances on a hillside. 

Many seeds are rendered conspicuous by being bright 
colored. This is true of the seeds of dogwood, black haw, 
wild cherry, and of berries and stone-fruits generally. 
Black seeds with the snow for a background are especially 
conspicuous. This is, of course, to attract the birds and 
effect the dissemination of seeds. 

Tumbleweeds break off close to the ground ; the weeds are 
generally round in shape. The wind starts to roll them and 
sometimes heaps them against obstacles in large heaps; as 
they roll the seeds are sown over the ground. Figure 108 
shows pampas-grass; its tassel shaped tops break off and 
are carried in the same way, sowing their seed as they go. 



Seed Dispersal. 



99 




Fig. 108. 

Pampas-grass; the tassel tops break off sooner or later one way or another and 
the wind scatters the seeds. 



LESSON LXVIII. 
Seed Dispersal. 

A Seed Dispersal Table. 

Sometimes edible fruits contain seeds the covers of which 
are indigestible ; these are swallowed by birds and animals 



100 



Nature Study. 



and dropped with their ejecta, Lesson LXIV. Sometimes 
as in the case of nuts and grain the seeds eaten are destroyed, 
but the plants bear far more than they need and many are 
dropped by animals by accident, Lesson LXV. Some seeds 
are winged, Lessons LV and LVI ; some have hairy append- 
ages, Lesson LVIII; some have hooks on the pods, which 
contain them, Lesson LXI; some float, Lesson LXIII, and 
some have special contrivances, Lessons LXVI, and LXVII. 

Exercise: Try to find a plant with no special help for 
seed scattering. 

Exercise: Fill out the following table for every plant in 
your neighborhood as the years go by. 





Seeds edible 
with indiges- 
tible seed- 
coats. 




T3 

C 
'$ 


Seeds floated 
by hairs or 
any form of 
pappus. 


*d 

O 
O 

■a 

% 

in 


c 

ft £ 


h 

o 
o 

•- s 

o rt 
<o > 


Walnut 




X 














X 


























Thistle 








X 
















X 


X 

































Read Chapter IV in Sir John Lubbock's 
and Leaves." 



Flowers, Fruits 



Plant Societies. 101 



LESSON LXIX. 
Plant Societies. 

Water Plants. 

Exercise: Visit several forests, especially to see if you 
find considerable numbers of the same kinds of trees growing 
in them. Do you know of a maple forest? a beech forest? 
an oak forest? Where can you find many willows, syca- 
mores, sassafras, gum or other sorts of trees growing to- 
gether? Do you know of a society of lilies, ragweeds, 
mallow,, blue-grass, cockle-burs or wild roses anywhere? 
A group of similar plants we name a plant society. Figure 
110 on St. John's river, Florida, is a palm society. This 
island of palms is known as "North Indiana Field." It is 
surrounded by shallow water in which reed societies grow. 
Locate as many plant societies within a half mile of the 
school-house or your home as you can. 

Figure 109 shows four societies: lilies in the foreground, 
then reeds; then willows; then deciduous forest trees, oaks. 
Why do these plants grow together? What advantages 
come to them because they grow together? Do not be in a 
hurry to answer these questions. Do not think that you or 
any one else can fully answer them. You will one day 
travel in warmer countries than this ; in colder ; in dryer ; in 
higher. There are places in your neighborhood that are 
drver than others; places that have a different soil from 
others. The south side of a hill is warmer than the north. 
From what you see at home and away you may easily learn 
that some plants grow in the water only or in very wet soils. 



102 



Nature Study. 




O w 

. O 

.5? & 



Plant Societies. 



103 



These are called water plants, hydrophites ; pond-scum, 
stonewort, duckweed, and white and yellow water-lilies are 

examples. 




Fig. 110. 

A palm society and a reed society. 



Exercise: See how many different plants you can find 
that are free-swimming. 



104 



Nature Study. 



LESSON LXX. 
Plant Societies. 

Microscopic Plants. 

All natural waters, ponds, streams, lakes and the ocean 
itself, contain plants and animals so small that single in divid- 




Fig. 111. 

Diatom shells. One of J. D. Moeller's slides, loaned by Bausch and Lomb 
Optical Co., and photographed with their one-inch photo-objective, x by about 60 

uals can only be seen by the microscope. This life is called 
Plankton. Diatoms, shells of which are shown in Figure 



Plant Societies. 105 

111, belong here. In all our streams, stones and sticks will 
be found covered with a gelatinous, sleek, yellowish-brown 
layer; this consists of millions of diatoms; there are also 
numberless free-floating forms ; their walls are made of the 
same material that sand is, — silica. These plants have 
died in lakes and bays in past ages in such numbers as to 
make rock formations 
several feet in thickness 
and many square miles in 
extent. The shells are 
sometimes so small, Fig- 
ure 112, that 41,000,000,- 

000 can occupy a single 
cubic inch. Many kinds 
of diatom shells are beau- 
tifully sculptured, and 
have been much studied 
on this account. Thou- 

Fig. 112. 
Sands Of different kinds Infusorial earth. These cylindrical di- 

1 n ., mi j atoms shown from both the side and the end 

nave been described and are so small that 41,000,000,000 can occupy 

r -. one cubic inch, x by about 500. 

figured. 

Exercise: In March every stone and blade of grass in a 
stream near my house is covered with this yellowish-brown 
growth to the thickness of half an inch or more. Find this, 
pass it through your fingers, and if possible, look at a little 
of it under a microscope. The quantity of microscopic life 
in a lake or other body of water is important, for it deter- 
mines the amount of higher life — fishes, for example, that 
it can support. 

LESSON LXXI. 
Plant Societies. 

One Plant Adapted to Live in the Water. 
Figure 113 is a view near Syracuse, Ind., in a bay of Tur- 
key lake. In the view here shown there were hundreds of 




106 



Nature Study. 







Plant Societies. 107 

water-lilies. The lake was of varying depth from one to 
something like four feet. These large leaves and flowers 
grow from rootstocks buried in the mud at the bottom of 
the lake in which the food necessary to produce them had 
been stored up. In this way the stem is preserved from all 
danger. The leaves and flowers all seem to have stems just 
long enough to bring them to the top of the water. Pull 






^/ 





Fig. 114. 
Surface view of stomata and epidermis of the pie-plant, x about 200. 



some of them up or row out to where the water is clear 
enough to permit you to see the bottom, and you will find 
that they are much longer than long enough to reach the 
water's surface ; the extra length of the flexible stem enables 
it to bring leaf or flower to the top in varying depths ; they 
can thus ride on the crests of the highest waves that are 
likely to come on the lake. They are buoyed up by air- 
cavities that make them lighter than the water. These 



108 



Nature Study. 



cavities serve also to conduct air down to the stem. Figure 
115 shows such cavities in a kindred species. Figure 114 
shows the stomata of leaves under a high power of the 
microscope. It is through these openings that air enters 
the leaves. In Lesson XXXV there is a cut of a cross- 
section of a stoma. Most leaves have these openings more 
numerous on the under side. This is, of course, not possi- 
ble for the water-lily ; its stomata are all on the upper side ; 
an adaptation to its life in the water. 




Fig. 115. 

Brassenia; cross-section showing air-spaces from stomata to parts under water. 
x by 20. 

Exercise: Find water-cress and compare its stem for 
stiffness and toughness with the stem of several air-plants of 
about its size. Take stonewort from the water or any other 
plant that grows upright in the water, and try to make it 
stand erect on land. Its weak stem is nicely adapted to 
support in the water, but it cannot stand in air. 



Plant Societies. 109 

LESSON LXXII. 
Plant Societies. 

Desert Plants. 

Xo life is possible in an entire absence of water/ but cer- 
tain adaptations enable plants to live for long! periods 




Fig. 116. 

Agave sisalina. nearly ready to flower. One million seven hundred thousand 
dollars worth of sisal hemp, the fibers of Agave have been shipped in a year from 
Progreso. Notice the 3-8 arrangement of its flowering branches ; the 9th over the 1st. 

without rain. They sometimes have, under a tough and 
close exterior which reduces transpiration to a minimum, 



110 



Nature Study. 



spongy tissues adapted to hold water for a long time. The 
lichens that grow everywhere on stones and trees have these 
qualities to a considerable extent. The century -plant is 
one of the most widely known plants that has its home in 
arid regions. 










# 



* .-— 



I/. 




Fig. 117. 

Cross-section of a purslane leaf. Notice the large reservoirs for water, between 
epidermic and chlorophyll cells. Does purslane flouish in dry weather? x about 
200. 



Exercise: Cut across an Agave leaf and notice the 
leathery outside to check the escape of moisture, the spongy 
inside to contain it and the strong spines to ward off the 



Plant ■ Societies . Ill 

attacks of browsing animals. Notice the reduction of sur- 
face in proportion to the size of the plant. Why do corn 
blades and mosses roll on a dry day ? How does this affect 
the exposed surface? If it reduces it, it checks to that ex- 
tent the escape of much needed water. Figure 1 1 7 shows 
a cross-section of a leaf of purslane ; a widespread plant that 
flourishes in the dryest season we have, and that every 
gardener knows is not easy to kill out ; our figure shows why ; 
the large cells labeled 1, are water reservoirs. These adapt 
the plant to our August weather. 

Read Charles Dudley Warner's "My Summer in a Gar- 
den" for a lierary man's view of "pusley." 



LESSON LXXIII. 
Plant Societies. 

Adaptation to Moisture. Land Plants. 

Between the reed growing in the water and the cactus on 
the arid plain, we have plants adapted to all degrees of 
moisture. Mosses grow best where the soil is wet. In a 
very rainy country like Scotland this may be on the tops of 
high hills. Cattails and other reed like plants grow in a 
foot or less of water or on the muddy shoals that immedi- 
ately surround water. Willows and sycamores grow in soils 
that may be termed anything from damp to dry; while 
many grasses and herbs and forest trees and shrubs grow in 
soils that we call swampy and on dry hills as well if pre- 
cipitation is distributed somewhat evenly throughout the 
year as it is in most of the United States. Conditions like 
ours are termed mesophytic conditions and the plant socie- 
ties are called mesophyte societies. As compared with the 
extreme water plants and desert plants, ours are vastly 
greater in variety, in abundance, and luxuriance of growth. 



112 Nature Study. 

The great characteristic of mesophytic vegetation is its 
expanse of green leaves. Figures 2 and 3 show us meso- 
phytic landscapes in their winter condition. The back- 
grounds of Figures 109 and 113 in their summer condition. 



LESSON LXXIV. 
Plant Societies. 

Some of the Advantages of Mass Life — Society Life. 

1. Cross-pollination with all its advantages occurs when 
large numbers of plants grow together. 

2. Small patches of herbs might be wholly stripped of 
seeds by animals and the species might thus be stamped out 
in a community, while larger areas could supply the demand 
and still have seed enough left. This reason applies, of 
course, to ravages of insects as well as other animals. 

3. Forests often resist a storm that easily uproots single 
trees that are larger and stronger, but unsupported. 

4. The competition of forest life brings every tree that 
survives to its best. 

5. The leaves that are shed and the limbs that fall make 
a covering for the ground that helps to retain moisture. 

6. The combined shade of a forest also helps to retain 
moisture. 

7. Is a tree warmer in the forest than in the open field? 

8. Do the conditions mentioned in 5, make the soil richer 
in the forest than it is about a tree in the open field? 



Plant Societies. 113 

LESSON LXXV. 
Plant Societies. 

A Walk in the Woods. Forestry. 

Select for this walk a day when the ground is sufficiently 
dry after copious rains have fallen. Get entirely out into a 
primitive forest. Leaves and sticks will be found entirely 
to cover the ground to the depth of several inches. Rake 
these aside and see how they conserve the moisture, prevent 
quick evaporation. Visit a large tree that has blown up 
recently by the roots ; estimate how deep in the ground the 
roots certainly go. Is not each one of these roots and root- 
lets a water way to conduct the rain down into the ground? 
Does the forest not make of the ground a gigantic sponge 
that receives and retains water which would otherwise hurry 
back to the rivers and oceans ? At another time visit an old 
mill site that no longer has water enough to run it. How 
many of these can you hear of in the neighborhood. Find 
out from the oldest settler about the springs that now are 
dry. Visit one. How many spring-houses are there in the 
neighborhood that now are without springs? It does not 
follow from all this that no forests should have been cut 
down. We had to have much of the ground for grain, but 
it does follow that we need forests; more than we have. 
They should be planted on the hills, the poorest land. We 
should begin to learn that before long we shall be compelled 
to plant forests as the old world has had to do. 



114 



Nature Study. 









.4*^* ^ , 






Fig. 119. 

A cross-section of smilax stem showing the bundles scattered in the pith, x 



Stems. 



115 



LESSON LXXV1. 
Stems. 

The Fibro -Vascular Bundle. 



Every one has whittled a cornstalk and seen the strings 
tougher than the pith, irregularly distributed through it. 

These are called fibro-vascu- 
lar bundles. Figure 118 is a 
cross-section of such a bun- 
dle from smilax. It contains 
large vessels arranged in the 
shape of a V, through which 
the sap rises to the leaves 
and flowers above. Beside 
the large conducting tubes 
two other kinds can readily 
be distinguished, the small, 
thick-walled fibres, enclosing 
the rest and some irregular- 
sized tissue which is general- 
ly to be found on the side of 
the bundle next to the bark; in this bundle the upper side, 
the open angle of the V. This is called the sieve tissue. 

Exercise: Cut off stems of the following plants: corn 
stalk, Trillium, lily and geranium, and set them in bottles of 
water that has been colored with a little eosin, — red ink will 
do. ^ After a few hours, and then daily for several days, take 
some* of them out and split them lengthwise and see if you 
can determine that the sap is rising through these fibro- 




Fig. 118. 
A fibro-vascular bundle of smilax. 
See text, x by 80. 



116 



Nature Study. 




vascular bundles. Let some 
of these stems have white 
flowers on them and see if, 
after a time, the red color 
does not appear in the veins 
and veinlets of the floral 
leaves. With a microscope 
the vascular tissue can be 
traced all the way into 
sepals, petals, stamens and 
pistils; you can often trace 
it all the way by the tracks 
of red with the naked eye. 
The right flower in Figure 52 

Brushes made from the stem of the was Striped in this Way with- 

saw-palmetto. The pith has been combed _ r J % 

out and the fibro vascular bundles are in three hours after it Was 
tough enough to be useful as brushes. 

These brushes are made in Melbourne, "placed in the ink 

Florida. ^ 



Fig. 120. 




Fig. 121. 

Corn bundles distributed irregularly as in smilax and palm x[ about 30. 



Stems. 



117 



Exercise II: Get a geranium leaf and break its petiole 
by a steady pull, but do not allow your hands to separate 
more than a quarter of an inch. The vascular ducts in the 
geranium are wound about by spiral bands tougher than 
the rest of the tissues; these will uncoil and the lower end 
of the petiole will be suspended by these coiled threads. 



LESSON LXXVII. 
Stems. 

The Arrangement of Fibro -Vascular Bundles in Exogens. 

Cut across a 
geranium stem 
one year old and 
compare the cut 
end with Figure 
122. The wedge- 
shaped bundles 
a, are ribro-vas- 
cular bundles . 
Notice that they 
are arranged in a 
circle around 

central pith in 
the geranium 
stem while they 
are irregularly 
scattered 
through the pith 
in the corn and smilax stems. This arrangement of the 
fibro-vascular bundles in rings is seen in all our forest trees ; 
it is the exogenous structure, the pine structure, the oak 




Fig. 122. 

Cross-section of geranium stem. Fibro-vascular 
bundles in a definite circle with pith cells (medullary 
rays) between, x about 18. 



118 



Nature Study. 







Fig. 123. 

A fibro-vascular bundle of Figure 122, more highly magnified. Pith at the left, 
then wood, cambium c, and outside of it the various elements of bark. 



structure. Compare the next lesson. The irregular dis- 
position of these bundles in smilax and corn pith acquaints 
us with the palm structure, the endogenous structure. 



Stems. 



119 



LESSON LXXVIII. 



Stems. 



The Growth of Wood in an Ex o gen. 




Fig. 124. 

\ cross-section of a one-year-old stem. It 
shows from within out pith, wood crossed by 
medullary rays and bark, blide and photograph 
by Mr. George Bond, x about 18. 



Cut across a one- 
year-old stem or 
branch of almost 
any tree ; Figure 124 
is taken from wil- 
low. Compare your 
cross-section with 
it. There is a cen- 
ter of pith nearly 
white, a; a ring of 
wood made up of the 
woody part of fibro- 
vascular bundles, b ; 
and a ring of bark. 
Figure 123 shows a 
fibro-vascular bun- 
dle in detail and we 
cannot learn about 
growth in a tree 



without a little study of it. The part from c, to b, con- 
taining the large clear openings, is wood tissues; from c to 
a, is bark tissues. Growth occurs at c, here the wood 
thickens on its outside and the bark on its inside; c, is the 
cambium layer. Figure 125 is a three-year-old stem. 
The pith is the white center; the wood is the three definite, 
half -inch, light rings that surround the pith; the dark, 
outer portion is the bark; the lines that mark so sharply 



120 



Nature Study. 



the divisions between the three portions of wood are caused 
by the fact that the cells are small and thick-walled in the 
fall when growth stops and large and thin-walled in the 
spring, when growth begins. The rings of growth accord- 



kS ; ' •' ' <^< 




Fig. 125. 

A three-year-old exogenous stem. It shows in addition to what Figure 124 does, 
the three rings of growth, x 18. 



ingly, however numerous they may be, are made up of 
circles of the wood portion of the fibro-vascular bundles, 
and each ring stands for one year's growth. 

Exercise for a school: Saw off a section from the largest 
log in the neighborhood. Find out from a carpenter how 
to polish and varnish the end. Count the wood rings, every 
one of which stands for a year of growth. Now count from 
the outside 411 rings and mark the ring that shows how 
large the tree was when America was discovered; mark in 



Stems. 



121 



the same way its size when Washington was inaugurated 
when Lincoln spoke at Gettysburg, etc.. for other impor- 




Fig. 126. 

A cross-section of a rootstock of fern showing its bundle-arrangement x 18. 



tant events of our history. There is such a section of a 
large tree in the South Kensington Museum on which more 
than a thousand years of English historv are chronicled. 



122 



Nature Study. 




Fig. 129. Fig. 128 

Fig. 127. 

Fig. 12 7. The heart-wood, a, sap-wood b, and bark of poplar (tulip). Fig. 128. 
Rings of growth in red cedar. Fig. 129. Rings of growth in the hickory. All 
these above a pine board that shows rings of growth well 



Stems. 



123 



LESSON LXXIX. 
Stems. 

Quarter -Sawed Oak. 

Notice in the cross-section of oak and mistletoe, Figure 
135, upper piece, there are radiating lines which run out 
from the pith toward the bark. These are called medullary 






Fig. 130. 

Quarter-sawed oak. The wide, perpendicular markings are the medullary rays 
as they appear in a radial section. 

rays. Quarter-sawed oak is oak that has been so sawed 
that the saw passed in the plane of these rays ; that is from 
the pith to the bark. The log is first quartered then a 
board or two is sawed off from the side of a quarter and 



124 Nature Study. 

when the grain begins to run out a triangular piece is cut 
off thicker at the bark so as to again bring the saw into line 
between the pith and bark. Figure 130 shows a quarter- 
sawed plank. These peculiar markings are caused by the 
medullary rays. When the tender end of a growing shoot 
is examined it is found to be all pith. The fibro-vascular 
bundles grow up later in the pith; this leaves pith cells 
between fibro-vascular bundles. These are the medullary 
rays. They do not look like the wood-cells and although 
single cells cannot be seen by the naked eye, masses of 
them can be. 

In Figure 122 the pith between fibro-vascular bundles 
shows well the medullary rays. As these bundles become 
more and more numerous the medullary rays become nar- 
rower and narrower; the radiating lines in Figures 124 and 

125 show medullary rays as they appear in cross-section. 
Exercise: Sketch medullary rays as they appear to the 

naked eye in cross, radial and tangential sections of some 
wood. A radial section is made when the knife or saw 
extends from the pith to the bark. A tangential when it 
is at right angles to a line from pith to bark. 

LESSON LXXX. 
Stems. 

Heart-Wood. 

Find a tree somewhere that is hollow at the butt and yet 
is still apparently growing and healthy. The wood usually 
found at the tree's center, and that has rotted and dis- 
appeared in this case, is the heart. See Figure 127 for the 
heart -wood a, the sap-wood b, and the bark of the poplar, 
(tulip). If you are not perfectly familiar with heart and 
sap-wood, cut into a tree or large limb and see the difference 
in color of the two. Notice that the sap-wood is softer 



Stems. 



125 



than the heart -wood; it is also lighter; the reason for this 
is the tissues of the sap-wood are younger and thinner 
walled. The heart -wood is not alive. 

Layer by layer the wood-tissues grew when the tree was 
young as explained in Lesson LXXVIII. The innermost 






Fig. 131. 

Bark of Sequoia. In this piece it is six inches thick, 
strip are one inch apart. 



The marks on the white 



layers were of course the older. Finally layer by layer it 
began to die on the inside, as it grew on the outside. Life 
and death have thus followed each other from within out, 
always separated by about the thickness of the sap-wood. 
Holmes says: 

"In fact there's nothing that keeps its youth 
So far as I know but a tree and truth." 



126 Nature Study. 

It would seem from the above that a tree does not keep 
its youth. Life is confined to a narrow zone on the inside 
of the bark and the outside of the wood. The heart is the 
ancestry of the living wood; the dead outer bark of the 
living bark. The wood entombs its forefathers ; the bark in 
one way or another sheds them. The entombed heart- 
wood strengthens the tree against storms. The bark dead, 
but not yet shed, protects it against blows and cold and 
heat and wet and bark-eating animals. Figure 131 shows 
the bark of the Sequoia gigantea, the big tree of California. 
This specimen is six inches thick. 

Exercise: Determine the number of years of growth of 
any tree ; wet or varnish a smooth cross-section and you 
will be able to count its rings of growth. 



LESSON LXXXI. 
Stems. 

Stem Disguises. 

A stem bears leaves, and roots grow out from it. These 
offices declare a vegetable stucture, a stem. It does other 
things, as for instance, it serves as a storehouse for food; 
other parts of the plant do this also ; but only a stem bears 
leaves and roots. Armed with a dictum like this we can 
recognize it under its varying forms. Figure 55 shows an 
underground stem. It has its advantages in the struggle 
with frosts and storms and rabbits; but the giants of the 
vegetable kingdom have got on otherwise. This was not a 
winning way. The stem is prostrate on the ground some- 
times ; this is the case with the stem of the saw-palmetto ; 



Stems. 12 7 

it floats under water sometimes, as in the case of Chara; it 
climbs by many methods, but all climbers are dependent. 
The princes of the vegetable world relied on none of these 
methods. At great expense to themselves they stand 
among their equals. The vine can only go where the oak 
has first gone. 

Exercise: Find the stem of fern, Solomon's-Seal, blood- 
root, violet. Is the Irish potato a stem or root ? the sweet 
potato? the artichoke? the Indian turnip? Those are 
stems that bear buds or leaves. 



LESSON LXXXII. 
Stems. 

Why the Yellow Violet Comes so Early in the Spring. 

"Of all her train the hand of Spring 
First plants thee in the watery mould, 

And I have seen thee blossoming 

Beside the snow bank's edges cold." 

Our common violet blossoms early also. The goldenrod 
does not bloom until autumn. We are entitled to ask 
why ; but the plants themselves are the only authority on 
the subject. 

Exercise: In early spring, gather the following flowers, 
dig every one up by the roots: Spring-beauty, wind- 
flower, liverleaf, pepper-and-salt, lamb's-tongue, trillium, 
violet, bloodroot, crowfoot and twinleaf , and any other kind 
of flower you can find blooming with or before them. Do 
they all grow from bulbs or thickened rootstocks or roots? 
Some underground source of nourishment? Can this be 
the reason why they can bloom so early? Does the crocus 
come early and from a bulb? Does the tulip? Does the 
lily-of-the-valley come from a rootstock? 

Provided as all these plants are with nourishment on 



128 Nature Study. 

which to grow they can bloom at once as soon as spring 
opens. Starting with only the patrimony of a small seed, 
of course the ragweed must have a long time in which to 
develop green leaves and roots and gather the necessary 
food for the exhausting process of seed-bearing. It should 
further be noted that all these spring flowers are content 
with small stature. If they wasted their substance in grow- 
ing large stems they could not bloom so early. 

But why should these spring flowers be in such a hurry? 
Several considerations are worth while in answer. If all 
plants grew at once and in similar places, there would not 
be room for them all. Where do you find these little spring 
flowers? Is it not in the woods and before the trees get 
their leaves ? They must make hay, their flowers and seeds , 
while the sun shines. Three weeks later and they could not 
see the sky at all. It is by fitting in to this one little niche 
of place and time that they can live at all. Patrimony, 
haste and smallness give us the fleeting beauties of our 
April days. 

You may sometime visit a tropical forest, that is always 
green and growing and so forever casts its dense shadow. 
You will find no spring-beauties or any other kind of flower- 
ing herb there. Everything that flowers, has had to climb 
as the forest climbs. Instead of small shrubs and* annual 
herbs, you will find vines that can mount up to sunlight 
on the top of an Amazonian forest. 

LESSON LXXXIII. 
Stems. 

Bark. 

If the birch tree is in your neighborhood notice that the 
bark easily strips off in horizontal strips. Find a shagbark 
hickory and notice that its bark peels off in vertical strips 



Stems. 129 

that come loose first at the bottom. (Is this to make climb- 
ing the tree difficult for the protection of the nuts ?) Notice 
that the sycamore occasionally sheds its bark and comes 
out in a new dress. What is cinnamon? Notice the iron- 
wood and see that its bark is shredded up and down the 
stem, the strings being very fine. Notice the bark of the 
sour-gum, persimmon, sugar, elm, oak, locust and walnut 
and see if they are not variously cracked and split up. 
How many trees can you tell by the bark' It would be fine 
nature study work for you to learn to tell them all this way. 

Why is the bark not as thick as the wood if a layer grows 
every year, as explained in Lesson LXXVIII. Why does 
the bark split on the tree in these various ways ? The tree 
has a bark when it is very young. Its outer bark is dead ; 
as the tree grows would it not be obliged to split? The 
bark of some trees clings much longer than that of others, 
but sooner or later and for one cause or another, the outer 
bark of all trees is lost. 

Exercise: Compare for thickness of bark red-oak, sugar- 
maple, beech, walnut, tulip and sycamore; trees of about 
the same size should, of course, be selected. 

LESSON LXXXIV. 
Stem Structure. 

Ashes. 

Every one knows that when we burn wood we have ashes 
left. Ashes consist of minerals of one sort and another. In 
the pioneer days there was a "hopper" at every house, in 
which ashes were leached to get "lye" for soap making. 
The "lye," "alkali," "potash" of the ashes acts on the grease 
in such a way as to make soap and glycerine. We some- 
times, when rainwater is scarce, make use of ashes to soften 
hard water, that is, to take the lime and magnesia out. 



130 Nature Study. 

The mineral matter of plants is absorbed from the soil in 
the water. The water escapes in transpiration and leaves 
the mineral matter behind. Consult again the lesson on 
transpiration, Lesson XLI. All summer long water, con- 
taining mineral matter, is absorbed by the roots of plants 
and given off in the form of vapor by transpiration, leaving 
considerable quantities of minerals in the plants. The 
same quantity of beech leaves burned in October will leave 
two and a half times as much ashes as if burned in May. 
Plants cannot grow and mature if they be deprived of these 
minerals; that is, if they are supplied only with distilled 
water. Plants deprived of potash lose the power to make 
starch. If they are deprived of iron the green coloring 
matter does not work properly. The living matter in 
plants always contains phosphorus and sulphur. We do 
not know all the duties of all the minerals in plants. Scour- 
ing-rushes owe their roughness to silica in the stem. This 
protects them somewhat from animals that would eat them. 
Some grasses are protected in the same way. 



LESSON LXXXV. 
The Root. 

The forms of the root are simpler than those of the stem. 
Why is this so? 

The turnip, the radish, the parsnip, etc., have one main 
descending root called the tap-root with subordinate 
branches. Other plants have many co-ordinate roots grow- 
ing out from the stem in all directions. Roots are some- 
times thickened and contain nourishment stored up for the 
plant the following year, as in the case of the carrot, rhu- 
barb, etc., or for new plants as in the case of dahlia or sweet 
potato. It may give us some trouble to determine whether 
these underground forms are stems or roots. If they bear 



The Root. 



131 



buds like the Irish potato and artichoke, they are stems. 
If they bear leaves like the onion, lily and the rootstocks of 
ferns, Solomon's-seal, and bloodroot, they are stems. 

Another office of the root is to hold the plant to the soil or 
other support. The power of the root to force its way 
through the hard earth is remarkable. The advancing root 




Fig. 132. 

Aerial roots of rubber-tree, Palm Beach, Florida. 

is^preceded by a root-cap which protects the growing point 
as it advances and penetrates the earth in its front. The 
poison ivy is held to its support by aerial roots that grow 
from the stem above ground. Aerial roots may be seen in 
Indian corn, in the rubber-tree of Florida, Figure 132, and 
in the famous and everywhere pictured banyan of India. 



132 Nature Study. 

The roots of this tree descending from branches form addi- 
tional trunks so that one tree may make a colony covering 
as much as ten acres. 

Still another office of the root is to absorb moisture ; this 
is done by the young root-hairs which are produced con- 
tinually on the younger parts of growing roots. These 
hairs come with the leaves and possess in the aggregate a 
surface in proportion to the leaf surface. This is why it is 
so difficult to successfully transplant a plant in full leaf. 
The absorbing root surface is lessened greatly by the injury 
to root-hairs, while the transpiring leaf surface remains the 
same. If plants are transplanted in the fall or spring, only 
so much leaf surface is called out when the growing time 
comes as corresponds to the root-hair absorbing surface. 



LESSON LXXXVI. 
Why Clover Helps the Soil. 

It has long been known that clover rejuvenates the soil. 
Farmers sow it in worn-out fields. The reason why this 
enriches the soil has been lately found out. Bacteria live 
in the tubercles, Figure 133, that grow on the roots of the 
pea, vetch, clover and some other plants. They have power 
in their growth to take nitrogen from the air for food; no 
plant or animal can live without nitrogen. When this 
becomes scarce in the soil ordinary green plants cannot 
grow well as they cannot take nitrogen from the air. It is 
equally true that no living thing can exist without carbon. 
Bacteria, as has been shown, cannot get this from the air. 
The bacteria growing in the clover root give us a fine in- 
stance of symbiosis ; the clover takes necessary carbon from 
the air for both itself and the bacteria. The bacteria take 
the necessary nitrogen for both themselves and the clover 



Why Clover Helbs the Soil. 



133 



and when the clover is plowed under, all the nitrogen of 
both is handed back to the soil in their decay. 



*v* 




X 



Fig. 133. 

Vetch showing tubercles on its roots in which bacteroids l?ve. 



Exercise: Find these tubercles on the roots of clover, 
vetch or some other leguminous plant. 



134 Nature Study. 

LESSON LXXXVII. 
Uses of Plants. 

Plants and Starch. 

We owe all our starch to plants. We obtain it from the 
seeds, stems, roots and leaves; our main supply comes from 
seeds. It is very easy to detect starch; it turns blue or 
black when treated with a solution of iodine. 

Starch is insoluble in cold water; a seed may therefore 
get wet and dry without loss to its food supply. Plants, 
however, cannot take solid food; but starch is easily con- 
verted into grape-sugar, which is soluble. In every seed is 
a ferment which at the right temperature and moisture can 
affect this change. The brewer takes advantage of this; he 
sprouts his barley and corn and lets the young plants turn 
their supply of starch into grape-sugar; then before the 
growing embryo can feed on it he raises the temperature 
and kills the embryo. But suppose the embryo is not 
killed; then the liquid grape-sugar which the plant has made, 
flows to every part of it and is by its vital action converted 
into cellulose, the main substance of which wood is com- 
posed. Cellulose has exactly the same composition as 
starch. Six parts of carbon and five of water make 
starch: an insoluble, pulverulent powder. Six parts of 
carbon andj sixof water make grape-sugar ; an easily soluble 
and therefore for the plant, easily transportable, substance. 
Six parts of carbon and five of water make cellulose, an 
insoluble substance, strong and durable as oak. Any one 
who has any penchant at all for 

"Adrairin' 'ow the world is made." 

ought to quite master this adaptation. Starch is an in- 
soluble substance that can be packed away in any available 
crevice. Properly add one part of water and it becomes 



Uses of Plants. 135 

soluble and can go to any part of the growing plant. When 
it gets to any desired part properly subtract 1 part of water 
and it becomes tissue, without which the plant as we know 
it, could not be. Sugar-cane is known nearly everywhere. 
If it were cut earlier it would contain starch only. Later 
its sugar would have gone to starch again in the seed, and 
to cellulose in its cell-walls. 

Exercise : Get of your druggist four grains of potassium 
iodide and one grain of iodine dissolved in an ounce of 
water. Boil a little starch in water and put a drop or two 
of the iodine solution in the starch solution ; it will turn blue. 
Now instead of the solution of starch, make a solution by 
boiling pounded grains of wheat, corn, oats, rye, rice, or 
bits of tapioca, in water. A drop or two of the iodine solu- 
tion will turn any of these solutions also blue. Any seeds 
mav be tried this way. 



LESSON LXXXVIII. 
Uses of Plants. 

Plants and Food. 

Of the three different kinds of food that we require, starch 
and sugar come entirely from the plant world. Our main 
supply of fats comes from animals; plants nevertheless 
furnish us much. Linseed-oil comes from flaxseed. Palm- 
oil from the palm tree. Castor-oil from the castor-bean. 
Sweet-oil from the olive. The main supply of vegetable oil 
comes from seeds. Hickory -nuts contain much oil. Sec- 
tions of the Brazil-nut under the microscope, show a large 
percent of oil. Peanut butter is now everywhere a com- 
mercial article. The manufacture of cotton-seed oil is a 
large industry. 

What do you know of the beet-sugar industry? Of the 



136 Nature Study. 

sugar-cane industry? Of "home-made sugar," the maple 
molasses industry? 

The third necessary food-stuff is protein. One main sup- 
ply is from lean meat, but all sorts of grain give large 
quantities. The living part of the grain consists entirely 
of protoplasm and there is always protein stored up as food 
for the embryo in the seed. The inner cells of a grain of 
wheat are filled with starch, the row next the bran contains 
protein entirely. 

Plants contain every kind of food necessary for life. 
Mushrooms consist almost entirely of protoplasm. 

Exercise: Put a little of the iodine solution mentioned 
in Lesson LXXXVII on a bit of mushroom ; it will stain it 
from yellow to brown according as the solution is weak or 
strong. It stains it the same color as it does your skin. 
Both are made of protoplasm. Many people eat mush- 
rooms, but as there is a kind that is poisonous, no one should 
ever eat them unless he knows he has an edible varietv. 



LESSON LXXXIX. 
Uses of Plants. 

Plants and Clothing, Medicine, etc. 

How many articles are you wearing now that are made of 
cotton? Find out how much cotton we raise in a year. 
Exchange greetings with a school in Georgia and get a cot- 
ton plant in return for some northern plant. Read the 
story of Eli Whitney. Raise cotton from the seed. 

Find out from the oldest man in the community all 
about flax, flax breaking, hackeling, spinning and weaving. 
Read a description of the hemp industry in James Lane 



Uses of Plants. 137 

Allen's "Reign of Law." Study the straw hat industry; 
at least we know that plants furnish the straw. 

It has also been shown that plants furnish us every sort 
of food we require, sugars, fats and albuminoids. They 
furnish us also an almost endless list of essences, condi- 
ments, stimulants, narcotics and poisons. Among these 
and in addition to them they furnish us many medicines. 
Treatises are written on this subject and courses of lectures 
are given on it in universities and medical schools. We are 
all acquainted with the use of slippery -elm bark, yellow- 
root, ginseng, and sassafras as medicines; some parts of 
many of our common plants are so used; may-apple, wild 
cherry, poke-root, Datura (jimson-weed Elecampane,,) etc. 
Many organic acids come from plants ; citric from the lemon, 
tartaric from the grape, malic from the berries of the moun- 
tain-ash, and acetic from apples, grapes and many other 
sources. Wood-alcohol comes from beech wood, ordinary 
alcohol from grains and many other sources, and a large 
number of other alcohols are derived from plant products. 
The acids above named often combine with the mineral 
elements that come up from the soil and form crystals in 
the cells. 



LESSON XC. 

Uses of Plants. 

Lumber and Fuel. 

How many kinds of trees grown in your neighborhood are 
sawed into lumber? How many are cut into shingles? 
Which are used for fence posts? for telegraph poles? for 
barrel staves, heads and hoops? for ax handles? which for 
mallets and mauls ? which are steamed and bent into bushel 
measures? which are generally cut for fuel? which furnish 



138 Nature Study. 

twigs for baskets? Gather a bundle of willow twigs. 
Notice that they are very brittle at the base and break off 
easily ; but that they are everywhere else tough and flexible. 
We can study the uses to which plants are put and from 
these we can infer their properties, or we can study their 
properties and make out from this study the uses to which 
they may be applied. Which wood is used for furniture, 
and which is hard and will take a polish and is beautiful 
when finished, are questions that have the same answer. 
What forest-trees are most used for shade-trees is one with 
asking which are the most beautiful or of quickest growth 
or cast the finest shadow. Let the poplar and oak stand 
for the houses we live in. The sugar and beech for comfort 
in the home. The cotton and flax for clothing. The 
wheat and corn for food. The elm and sassafras for medi- 
cine and Whittier's "Palm" is not fable: 



"Is it the palm the cocoa-palm, 

On the Indian Sea by the isles of balm? 

Or is it a ship in the breezeless calm? 

"A ship whose keel is of palm beneath, 
Whose ribs of palm have a palm-bark sheath, 
And a rudder of palm it steereth with. 

"Branches of palm are its spars and rails, 
Fibres of palm are its woven sails, 
And the rope is of palm that idly trails! 

"What does the good ship bear so well? 
The cocoa-nut with its stony shell, 
And the milky sap of its inner cell. 

"What are its jars so smooth and fine, 
But hollowed nuts, filled with oil and wine, 
And the cabbage that ripens under the Line? 

"Who smokes his nargileh, cool and calm? 

The master, whose cunning and skill could charm 

Cargo and ship from the bounteous palm. 

"In the cabin he sits on a palm-mat soft, 
From a beaker of palm his drink is quaffed, 
And a palm-thatch shields from the sun aloft! 

"His dress is woven of palmy strands, 

And he holds a palm-leaf scroll in his hands, 

Traced with the Prophet's wise commands! 

"The turban folded about his head 

Was daintily wrought of the palm-leaf braid, 

And the fan that cools him of palm was made. 



Uses of Plants. 



139 




Fig. 134. 

"Of threads of palm was the carpet spun 
Whereon he kneels when the day is done, 
And the foreheads of Islam are bowed as one! 

"To him the palm is a gift divine, 
Wherein all uses of man combine, — 
House, and raiment, and food, and wine! 

"And, in the hou/ of his great release, 
His need of the palm shall only cease 
With the shroud wherein he lieth in peace. 

" 'Allah il Allah!' he sings his psalm, 
On the Indian Sea, by the isles of balm; 
'Thanks to Allah who gives the palmP" 



Exercise : What plants do for us all the things the palm 
is said to do for the Indian? 



140 



Nature Study. 

LESSON XCI. 
Parasitic Plants. 



Many plants cause disease in other plants by growing on 
or in them and living at their expense. Every one is fam- 
iliar with the heads of black smut that live on wheat, oats 




Fig. 135. 

a. A section through a branch of mistletoe growing on oak; the mistletoe is to 
the left, the oak to the right. Mistletoe is a green-leaved parasite, lives on crude 
ascending sap it gets from the oak's fibro-vascular bundles. Chlorophylless para- 
sites strike through the bark only and live on the living matter of the plant in the 
cambium layer; b shows an end view of Figure 12 7. c is a palmettolbrush giving 
an end view of the bristles (fibro-vascular bundles). 



Parasitic Plants. 141 

or corn. The shepherd's-purse that grows every where is 
often infested by a white rust ; this same rust grows on 
radishes and causes the blossoms, seeds and leaves to swell 
greatly by the multiplication of its organs of reproduction 
within the tissues of the radish. 

Cluster-cups, very beautiful under a low power of the 
microscope, grow on gooseberry and other sorts of leaves. 




Fig. K : 6. 

Forms of bacteria; a, globular; b, a long red: e, a :hcrt red; d, a bent red; e. a 
spiral, x 2C00. 

Lilac leaves are often covered by a grayish pow T der which is 
seen under the microscope to be a parasite. Blackberry 
leaves are often covered with a red rust which is a parasite. 
A study of these plants requires a knowledge of how to use 
the microscope, but their large colonies can usually be seen 
with the naked eye and we should learn how to recognize 
their presence in this way. 

The disease germs known as bacteria, are microscopic 



142 



Nature Study. 



plants. Figure 136 shows four different forms which they 
assume; they are globular, like a; long rods, like b; short 
rods, like c\ bent rods, like d\ and spirals like e. This 
photograph was made from tooth scrapings. 

Figure 138, shows the bacillus that causes consumption. 
It was discovered in 1881 bv Robert Koch, a German bac- 





;t * #1 ft 



%-m m, 



§^> 



Fig. 137. 

Anthrax being devoured by the white blood-corpuscles of a frcg. 



x about 4G0. 



teriologist. He has made it possible for us to make a cer- 
tain diagnosis of this disease in its earliest stages and in 
many cases to arrest its development. Some knowledge of 
his life and labors should be known to every one. 

Figure 137 shows the bacillus that causes splenic fever in 
process of being devoured by the white corpuscles of a frog's 



Parasitic Plants. 143 

blood. A mouse if inoculated with this bacillus, dies of the 
disease. A frog does not contract it at all ; the reason seems 
to be that the white corpuscles of the frog's blood eat these 
bacilli up. This bacillus forms spores when conditions for 
its living become unfavorable, as when its food begins to 
give out. These spores are able to resist a degree of heat 
and cold, which the bacillus cannot ; these spores serve it as 



i' A C 






f .-t 



I 



iio- 



Fig. 138. 

The long jointed rods are consumption germs, x 2000. 

the spores and seeds of higher plants serve them, that is, 
they enable it to survive extremes of heat, cold or dryness, 
which the bacillus itself could not. We owe to Pasteur, a 
French bacteriologist, the conquest of this disease, of the 
chicken cholera, of the silkworm diseases, and of hydro- 
phobia. It was his work that first gave us the cause of 
fermentation and decay. 

Read the "Life of Pasteur" by his son-in-law, V. Radot. 

Parasitic plants should be distinguished carefully from 



144 Nature Study. 

epiphites; that is, plants which grow on but not into other 
plants. Epiphites owe support only to their hosts. Para- 
sites owe sustenance also to their hosts. Tillandsia, Span- 
ish moss, so common in Florida, is an interesting example 
of an epiphite. 

LESSON XCII. 

The Plant's Chief Work. Saprophytic Plants. 

A plant is a machine for storing the energy of the sunlight. 
We can consume the plant, and its stored energy gives us 
strength; we can burn it in our fires and it gives us heat, 
which we can utilize to warm our houses or to do our work 
or to give us light. Coal is the plant-stored energy of past 
ages; this distinctive plant duty, the storing of energy, is 
done only by green plants. Many plants have, however, 
become degenerate by feeding on organic food and leaving 
off entirely the storing of sunlight. Mushrooms, Figure 
139, are among such plants. They cannot grow on a min- 
eral soil as green plants can. They do not need the light as 
green plants do. Mucor, the white mould one sees so 
abundant about stables, on foggy, wet summer days, grows 
vigorously in the depths of Mammoth cave, where no ray 
of light ever comes. These plants are destructive; they 
spend only ; green plants are constructive ; they make far 
more than they spend. This is the green plant's mission in 
the world. They constantly accumulate beyond their own 
needs what animals and chlorophylless plants spend. 

Exercise : Go to a small stream in midsummer a half mile 
or so below a sewer mouth and note what grows in the 
water all the way up to and into the sewer. You meet first 
green and brown algae, scums and microscopic plants; next 
vou see deep blue green plants in large masses; they are 
Oscillaria, mainly; they often so cover the bottom as to 
make the water appear black. You then find near the 



Parasitic Plants. 



145 




146 Nature Study. 

sewer's mouth and as far in it as you can see, white^ stream- 
ers that live on the decaying matter contained in the sewer 
water. 

The mushroom and its allies are degenerate plants. They 
are not doing plant duty. If they live on living plants or 
animals, we call them parasites. If, like the mushroom, 
they live on decaying vegetation, or other dead organic 
matter, we call them saprophytes. The mushroom has 
chosen the line of least resistance which cannot be chosen 
by plant, animal or man, except at the expense of its birth- 
right. The oak faced the strenuous life; the mushroom 
dodged it. Read the introduction to Hawthorn's "Scarlet 
Letter." 



LESSON XCIII. 
Chlorophyll. 

The general green color of leaves is due to green granules 
in the cells. Figure 56 shows these granules. They are 
living bodies; they increase by division just as many low 
forms of life do. They are simply colored protoplasm. 
Alcohol will extract their color from them after which they 
can be stained other colors. The upper side of the leaf is 
greener than the lower because, for one reason, these gran- 
ules are far more numerous on the upper side. They are so 
small that they can be seen with a compound microscope 
only. They can be well seen in leaves of moss simply by 
mounting the leaves in water. They can, of course, also 
be seen in all sections of green leaves or of other green parts 
of plants. They are very fantastically shaped in some of 
our commonest green pond scums, Figure 140. 

The chlorophyll granules are the starch makers. They 
sometimes contain so much starch that a solution of iodine 
colors them so deeply as to mask their green. Starch is 



Chlorophyll. 147 

composed of carbon and water. These are in some unknown 
way brought together in chlorophyll granules. The carbon 
comes from the carbon dioxid of the air. The process is 
named from three Greek words, which mean a putting 
together in sunlight, photosynthesis. We ought sometime, 
to see these little granules, and find out how incalculably, 
unthinkably numerous they are in a single tree and to 
remember that it is to their combined action that the earth's 
organic upbuilding is due. 



p \mA 






mm 



h- i& 



Fig. 140. 

Filaments of Spirogyra getting ready fcr conjugation. The f.laments can adapt 
themselves to the distance between them by length of tube, x about ICO. 

Exercise : If the following experiment is difficult of per- 
formance, nevertheless it will help us to understand how it 
is learned that starch is made in the sunlight by the green 
leaf. Immerse a leaf from a potted plant, in Shimper's 
solution, see below, at about 2 o'clock p. m., and notice that 
it gives a starch color ; the leaf should have been all morning 
in the sunshine. Keep the same plant in the dark from one 
morning until 2 o'clock the next afternoon and then im 
merse a leaf in Shimper's solution. It will show no starch 



148 



Nature Study. 



at all, or very little. Now take a leaf and darken a spot on 

it between two slices of cork, thus, Figure 141, from 10 

o'clock until 2 the next day, 
keeping the plant all the time in 
the sunshine. Immerse this leaf 
as before in Shimper's solution 
and the starch color will show 
everywhere except in the spot 
covered by the cork, which had 
been in the dark. 

Shimper's solution: Dissolve 
8 grams chloral hydrate in 5 cc 
of water and add to this 1 cc of 

iodine solution; see Lesson LXXXVII for the formula of 

this solution. 




Fig. 141. 

Method of shading a spot on a 
growing |iea [between [pieces J of 
cork. Alter Detmer. 



LESSON XCIV. 



Protoplasm. 

• Differences Between Animals and Plants. 

If one considers a cow and a tree the difference is plain 
enough; one is fixed, the other can come and go; one ab- 
sorbs liquid and gaseous food only, the other can take solid 
food into its body and by processes of its own, reduce it to a 
liquid state; one can live on inorganic food alone, that is, 
what it gets from the ground, water and air ; the other must 
live on organic food. The plant utilizes and stores the sun's 
energy; the animals utilize the energy of other animals or 
plants. The cow has a specialized nervous system. She 
knows, feels and wills. The tree seems to lack these things. 
These manifest differences between plant and animal life at 
their extremes all vanish as we approach the boundary line 



Protoplasm. 149 

between them as we consider the more similar forms of both. 
Animals generally require organic food, but so also do all 
fungi, mushrooms, rust, smuts, mildews and moulds. 
Animals generally eat solid food and plants generally do 
not, but some plants like Venus's fly-trap and Drosera can 
surround and digest solid food. Plants are generally fixed 
to the soil where they grow, but so also are many kinds of 
hydroids, corals, sea-fans, etc., and many kinds of plants 
move freely at some stages of their lives, as freely as ani- 
mals do. It has always been true that naturalists could 
not agree as to whether certain forms are animals or plants. 
From time to time it is agreed that certain forms hitherto 
regarded as belonging to one kingdom, shall be set down as 
certainly belonging to the other. It has often been pro- 
posed to have three kindgoms, a plant kingdom, an animal 
kingdom and a plant-animal kingdom ; and this would long 
ago have been done but for the fact that it would simply 
have multiplied the difficulty by two ; it is now impossible 
to determine in all cases whether a given form should be 
called animal or plant; if three kingdoms were recoginzed 
it would be impossible to distinguish animals from plant- 
animals and plants from plant-animals. The impossibility 
of separating plants and animals except by arbitrary 
bounds, is one reason why modern science recognizes the 
term Biology, the science of life. 

That the animal moves is probably an adaptation to its 
food supply, which is, in general, solids that it must go to 
get. 

That the plant is fixed is likewise perhaps an adaptation 
to the fact that its food-stuffs are liquids and gases that can 
and do come to it. 



150 Nature Study. 

LESSON XCV. 
Protoplasm. 

The Respiration of Plants. 

It was thought for a long time that plants consume car- 
bon dioxid in respiration and give off oxygen and that 
animals consume oxygen and give off carbon dioxid. This 
is wrong, but it is so nearly like something that is right that 
it is hard to correct. Plants retain the carbon of carbon 
dioxid and give off oxygen during the day time, but they 
do not consume the carbon in breathing ; they make it into 
food on which both they and animals can live ; they use it 
in their work of photosynthesis. The part of the plant, 
however, which lives must consume oxygen. During the 
night plants give off carbon dioxid as a result of their breath- 
ing just as animals do. During the daytime their breathing 
is disguised by the larger work they are carrying forward; 
during the day they give off carbon dioxid in respiration, 
but consume in photosynthesis more than they give off. 
Plants that are not green and cannot therefore do photo- 
synthesis give off carbon dioxid all day long just as animals 
do. 

Exercise I. Make lime-water by soaking a pint of lime 
in two quarts of rain-water a few days. Pour off the clear 
lime-water and keep it in a tightly corked bottle. Pour a 
little of this water into a test tube or homeopathic vial, 
breathe on it and shake it up and it will turn milky on ac- 
count of the carbon dioxid in your breath. Now soak two 
ounces of peas by measure, in warm water over night and 
place them for twelve hours in a six-ounce bottle, well 
corked. Decant the air from this bottle into a little lime- 
water as before and shake it; it becomes milky. The 
sprouting peas give off carbon dioxid also. 



Protoplasm. 151 

Exercise II. To show that chlorophylless plants give off 
carbon dioxid, put a growing mushroom in a fruit can, seal 
it and after a day try the air of the can with lime-water. 

Exercise III. Put a healthly potted plant in a fruit can, 
close the can tightly and set it where it is perfectly dark for 
twelves hours and test the air in it for carbon dioxid. If 
it is not put in the dark, carbon assimilation will disguise 
respiration ; but the respiration will not be any the less real 
because it is disguised. 

LESSON XCVI. 
Protoplasm. 

The Cell. 

Among the great achievements of the nineteenth century 
is the discovery of protoplasm and the proof of its identity 
in animals and plants. Protoplasm has been defined as 
"the physical basis of life." We can, perhaps, better get 
at the fact if we say it is the thing that lives, the only thing. 
Protoplasm makes starch and fat, the cell wall in all its 
forms and all its varied cell contents. It is a granular, 
nearly transparent substance ; it can surround a bit of food 
and digest it ; it can grow and divide so that what was one 
individual, becomes two ; or what was one cell, becomes two, 
Figures 143 and 145. Two separate masses can combine 
so that two cells become one. Figure 140 shows two fila- 
ments of a common green pond-scum which have grown 
passage ways from one to the other through which the con- 
tents of two cells can unite ; the process is going forward at 
the top of Figure 147 ; it is completed at the bottom of the 
same figure. Protoplasm is sensitive to heat and cold, to 
an electric current or any sort of bodily contact. It re- 
quires food and oxygen to carry on its life processes ; it can 
work in the dark as well as in the light; indeed most of it 



152 Nature Study. 

is shut up in the more or less opaque walls of plant or animal 
cells and does its work there ; it can carry on the processes 
of assimilation and excretion. It is contractile; it can 
slowly move about from place to place when free or it can 
move about within the cell wall that confines it. It can 
build cell by cell the oak or the elephant and it is its ac- 
tivities that enable all living things to do whatever they can 
do. It can surround itself with a wall of wood, of phosphate 
of lime as in bones, of silica. Goethe, who explained so well 
the transformations of the leaf, thought there must be 
somewhere a type plant by the modification of which all 
plants are made. This type plant, "Urpflanze," as he 
named it without seeing it, is the typical plant cell. When 
he sat in his gardens and^ talked about them but could not 
find them, millions of them clothed his trees from root to 
crown, for the green coating on bark and fences in damp 
countries and localities often consists almost entirely of 
them. Multiply them enough and modify them enough 
and the miracle of the vegetable world is all about us ; and 
cells in the presence of the proper stimuli can be shown to 
be able to do this multiplying and modifying. 



LESSON XCVII. 
How Plants Multiply. 

The Asexual Way. 

Go first to the strawberry and see the runners, prostrate 
stems that grow out along the ground and take root at a 
suitable distance from the parent stem. This is one way 
that a plant can become two. Figure 142 shows a similar 
mode of multiplying in the water hyacinth, a plant found 



How Plants Multiply. 



153 



in abundance on the St. John's river in Florida. The 
petioles of the leaves swell out into large floats (a) and by 
their number and arrangement keep the plant upright and 
prevent it from sinking. The runner has sent roots down 
into the water six inches away from the parent plant. 
This plant has so spread over St. John's river as to seriously 
interfere with navigation and the government has made 




Fig. 142. 
Water hyacinth. See text. 



an appropriation for the year 1903 for the purpose of 
stamping it out. 

Go next to the raspberry, or if you know it, to the walk- 
ing-fern ; the raspberry bends its tip over to the ground and 
the fern its to the rock wall on which it grows and they alike 
take root at a distance from the home-plant and one be- 
comes two. Cut off a number of limbs from a willow and 
plant them along a stream; they will grow into trees. Are 
they new trees? Individuals? If they had grown on the 
old stem would thev have been new trees? Is a tree a 



154 



Nature Study. 



colony? Budding consists in taking uninjured buds from 
one tree and planting them under the bark of another tree. 
Grafting consists in taking little shoots from one tree and 
properly planting them in the limbs of another. Suppose 
wine-sap, bellflower and five other varities of buds are 
planted on the seven limbs of a seedling and grow into 
thrifty, fruit -bearing branches ; what sort of tree is this ? Is 




Fig. 143. 
Filaments of Nostoc, a blue-green alga in process of cell division, x 400. 



it seven trees? Is every bud an individual in the colony 
that goes to make up a tree? 

There are many one-celled plants that have only this 
asexual way of multiplying. Figure 143 is a blue-green 
alga that may be found in gutters, often along the street or 
damp places in greenhouses; it is called Nostoc. The cells 
of the filament here shown are in several stages of division. 



How Plants Multiply. 



155 



Figure 145 shows a 
parasite plant that is 
often found in sores on 
the body; it is often 
coughed up by patients 
suffering with sores on 
their lungs. Several 
stages of cell division 
can be seen. 

Yeast owes its prop- 
erties to a one-celled 
plant that lives and 
grows in suitable liq- 
uids. The yeast-plant has a peculiar way of dividing, 



!■ . # 




• 

.'V 

> 






; 


• 

* 


1 


f 


.* 




* 

• 


*• 


• 


m 



Fig. 144. 

Yeast-cells in process of budding, 
text, x 200. 



See 




Fig. 145. 

Filaments of Streptococcus dividing. The kinship in form of Nostoc and Strepto- 
coccus is one good reason for regarding bacteria as degenerate plants. Highly 
magnified. 



156 



Nature Study. 



called budding, Figure 144; a very small bud appears on 
one side, which grows until it is as large as the mother-cell. 
It is called the daughter-cell; in actively "coming" yeast it 
often happens that a daughter-cell begins to bud before it 
separates from its mother. This is true of a granddaughter 
and great granddaughter-cell also before any of them have 
let go, so that it is possible to get four or five generations in 
one picture. 



LESSON XCVIII. 
How Plants Multiply. 

The Sexual Way. 

Another very different mode of reproduction 
is by the union of two cells one of which is 
known as the male cell and the other as the 
female. Figure 146 shows two exactly similar 
plant cells uniting on neutral ground. This is 
the simplest possible sexual multiplication. 
The new individual formed by their union will 
divide many times asexually to form new gen- 
erations. In this instance it is not possible to 
say which is male and which is female, for both 
look and act exactly alike. 

Figure 147 shows two cells uniting, but not 
on neutral territory. The cell contents of all 
cells in the left filament pass entirely through 
the funnel tube to the right filament. Both 
cells help to make the connecting tube; they look alike, but 
do not act quite alike; there is physiological, but not ana- 




Fig. 146. 

Reproduction 
by cell union 
on neutral 

ground , no 
distinction of 
male and fe- 
male. 



How Plants Multiply. 157 

tomical, distinction of sex; the left filament is the male 
filament. The egg-shaped bodies in the female cells are 




Fig. 147. 

Spirogyra. Reproduction by cell union in the home of the female cell; physi- 
ological distinction of sex, not anatomical; the filaments look alike, x 200. 

new one-celled plants ; the parent cell walls will decay and 
after a rest these will all grow by division into new fila- 
ments of pond-sTiim. 



158 



Nature Study. 



/>:* 



jOiY 



fcmt 






Figure 148 shows male and female 
organs of a plant in which there is 
anatomical, as well as physiological, 
distinction of sex; here the female 
cell not only stays at home and 
awaits the coming of the male, but 
it is larger, better fed and better 
housed. 

Any number of illustrations could 
be added showing progress in dis- 
similarity between the male and 
female cells. This difference is in 
size, the male being the smaller; in 
activity the male being the more active; in protective 



<> 

Fig. 148. 

Oedogonium, a common 
green alga attached to sticks 
and stones. 1, the small 
motile male cell goes to the 
large female cell. 2, Ana- 
tomical and physiologica 
distinction of sex. After 
Oltmans. 



*■■■« "„ "<•■■•■ ';■■■■. 



?r .«w • 









•;•;-• r r •• 






. ^+:i&r'\ V \ '. * *.: XJ - V . * ' . - - : * 1 



Fig. 149. 

Section through the well-protected, well-fed home of a female cell of Erigenia. 
The section is through the micropyle through which the male nucleus enters. Slide 
prepared by Mr. Charles H. Frazee. x 100. 




-•' "--■-. 



^ ' \$ 






, V 



v*< 






Fig. 150. 

Cross-section of the summit of a male moss plant, a, an autheridium containing 
perm-cells, x 200. 




Fig. 151. 

The same as Figure 150, with antheridium discharging sperm-cells, x 200. 



160 



Nature Study. 



coverings and mode of nutrition, the female being the better 
cared for and better fed. Figure 149 shows the safe and 
well lardered house of the female cell of the harbinger-of- 




Fig. 152. 

Two sperm-cells of moss very highly magnified. After Atkinson. 



spring, Erigenia bulbosa. Figure 150 shows the summit of 
a male moss stem, (a) is a longitudinal section of an an- 
theridium containing sperms. Figure 151 shows an an- 

theridium bursting and dis- 

; charging the sperms. A sim- 
ple sperm, when mature, re- 
sembles Figure 152. This 
swims by means of its cilia 
into the archegonium of the 
female moss head which 
closely resembles Figure 153. 
It reaches the egg-cell at the 
bottom of the archegonium, 
and fertilizes it. It will be 
seen by these figures that 
among mosses the differences 
between the egg-cell and the 
sperm-cell are very great. 

Figure 154 shows at (a) 
the fertilized egg-cell of the 
harbinger-of-spring. 

All higher plants, mosses, 
ferns and flowering plants 

Archegonia of a liverwort, Marchantia; produce in One Way Or an- 

1 , an almost longitudinal section through ,, -. ,. 

the entrance; 2, passes through an egg- Other and. at One time Or 

cell. These are ver , similar to the same ,.. . ., . « . P , • . 

organs in moss, x 200. another in their life history, 




How Plants Multiply. 



161 



such a fertilized egg-cell, and from this cell new plants 
grow. 




Fig. 154. 

A section of a young plant of Erigenia bulbosa during the resting stage after the 
egg-cell had been fertilized. Slide prepared by Mr. Charles Frazee. x 7 50. 



Figure 155 shows a young embryo of a smartweed ; the 
fertilized egg-cell has divided twice so that it now consists 
of four cells. Figure 156 shows a stage considerably more 
advanced. It is thus by cell division, unequal growth, in 
different parts, unequal growth in the cells themselves, and 



162 



Nature Study. 



the development of walls of varying thickness and quality, 
that the plant with its organs and tissues is matured. 

It is worthy of note that the pistil which houses the female 
cell, the macrospore, grows at the center of the receptacle, in 
the direct line of the food supply ; the stamens always grow 
to one side and are accordingly, never so well-fed; they 







Fig. 155. 

A young smartweed after the fertilized cell had divided and the two resulting 
cells had again divided. Slide prepared by Miss Ruth Trueblood. x 750. 



often grow on the sepals or petals or even on the ovary 
itself, and must be content not only with a side flow of sap, 
but they must share this side flow. 

A fine study for any one with a microscope would be to 
determine the relative amount of conducting tissue that 
leads to a stamen and a pistil. To get the real ratio, these 
amounts should then be divided respectively by the number 
of pollen-grains the stamens bear and the number of seeds 
the pistil can bear. 



How Plants Multiply. 



163 




Fig. 156. 

Many-celled stage of a young plant of twinleaf. Slide prepared by Mr. Charles 
Frazee. x 750. 



164 Nature Study. 

LESSON XCIX. 

Growth from the Cell to the Tree. 

Cells have been shown in process of division. Sometimes 
they divide in one plane only and we have then a filament 
like Figure 143. Sometimes they divide in two planes only 
and we have flat plants of varying length and width but 
only one cell thick. Some moss leaves, except in the region 
of the veins are such structures. Sometimes cells divide in 
three planes and then we have figures of varying length, 
breadth and thickness like most of the plants we know. 
The almost infinite variety of shapes in plants arises from 
two causes. First, the cells divide in their different planes 
a different number of times, many divisions in one plane, 
giving length, fewer in another giving breadth, and fewer 
still in the third, giving thickness. Second, the cells them- 
selves have three dimensions. They are solid bodies and 
they may grow to have very varying dimensions. The 
typical plant cell is globular, all its dimensions are the same. 
Plant cells vary in their shapes from this typical form so 
much that their shapes could not have been conceived of or 
believed to be if they had not been seen. The various 
accompanying microscopic figures show other cell shapes. 



LESSON C. 

Cell Duties in a Many-Celled Plant. 

In a one-celled plant its life processes are all carried for- 
ward by the one cell. It must breathe ; it must assimilate ; 
it must construct a wall if it has one ; it must store up food ; 
it must contract if it is to have voluntary motion; it must 
reproduce. As soon as cell union comes, with a vital union 



Cell Duties in a Many -Celled Plant. 165 

between two or more cells, these duties can be divided out 
among many or fewer different cells ; a tree, for example, has 
protective tissue, the bark, some cells of which do nothing 
else ; it has conductive tissue that distributes sap to all parts. 
It has supporting tissues that discharge no other duties than 
that of holding the vital parts in position. It has secreting 
cells such as produce the milk of the mulberry, the resin of 
the pine, the nectar of the flower, etc. It has storage cells 
for starch, fats, crystals, etc. It has assimilative tissues 
and reproductive and many other sorts. This division of 
duties can be but slight in one-celled creatures. It can 
only be between different parts of the same cell which is 
generally too small to be seen by the naked eye. Cell union 
has its advantages and disadvantages. In Nostoc and 
other similar filaments each cell is independent except for 
purposes of defense and buoyancy. It is a sort of defensive 
alliance that leaves every member of the community free 
to manage its own internal affairs. The community life in 
Spirogyra has for its advantage the extra protection and 
support of the common wall. The disadvantage is that 
individuals are subject to the accidents of the colony. If 
we could study all plants gradatim from the simple one- 
celled Protococcus to the oak, we should find very gradual 
steps in the formation of what may very fairly be called the 
combined trusts that go to make the oak. The root trust 
gathers the food containing moisture from the soil and 
hands it on; it also holds the oak in place and lends its 
reservoirs as storehouses. The plant has so completely 
given over these duties to the root that it is dependent on 
it for at least two of them. The chlorophyll is a trust for 
storing the energy of sunlight, so complete that no other 
part of the plant can take its place even partially or tem- 
porarily. The great advantage of these combinations is 
without question; because all the plants which are large 
enough to be seen by the naked eye have adopted them, 



166 Nature Study. 

and the higher the plant in the life scale the more complete, 
numerous, and complex are these combinations. Plant 
organization has been long ages in perfecting the division 
of labor and the co-ordination of its tissues and organs. 
Society's organization may one day be equally just and 
perfect. 

LESSON CI. 
Young Plants. 

Every one has noticed the difference between the green 
gosling and the white gander, which it becomes. A chick 
does not much resemble a chicken. There is a difference of 
like meaning and importance between young and old plants. 

Exercise I: Plant cucumber, squash, pumpkin, and 
several kinds of muskmelon and watermelon seeds. As 
soon as they come up, if you see any remains of the seeds, 
remove them and try to tell by the young plants what each 
one is. Try when they have only two leaves; try again 
when they bear four leaves. Watch them as they grow. 
Visit patches of all these things growing in the field and see 
if you can distinguish them. You will learn by this exercise 
that young plants resemble each other much more than 
old ones. 

Exercise II: Gather mulberry leaves from a large tree, 
but not on vigorous young shoots. Gather other leaves 
from young trees. The leaves on young trees are lobed; 
on old trees they are not. 

Exercise III: Learn to tell several varieties of oak by 
the leaves. Try now to determine these several varieties 
when they are not more than a year or two old, and it will 
be clear that the young does not resemble the old and that 
the young of different species closely resemble each other. 

Exercise IV: Take the most irregular flower you can 
find, a larkspur for instance, or locust, or bean blossom. 



Young Plants. 167 

Learn the shapes of all the petals of the adult flower. Now 
examine the petals in the bud. The lesson is the same, 
young petals resemble each other. 

Exercise V: Notice the branching of a soft maple, called 
also a silver maple ; its branching is deliquescent like that of 
the elm. Notice the branching of the sugar-maple; it is 
excurrent like that of the fir. Now find a young soft maple 
and you will find that its branching is excurrent, like the 
sugar-maple's. You will learn from this lesson that the 
young of one species sometimes resembles in one or more 
particulars the adult of another species. These are useful 
lessons in the science of embryology. It has been found 
out as a principle that the growing young that resemble 
each other longest are the nearest akin. Try your water- 
melon, two varieties of muskmelon and cucumber seeds 
again and see how old they are when you can easily dis- 
tinguish the watermelon from the rest. How old are they 
when you can distinguish the cucumber? How old when 
you can distinguish the two varieties of muskmelon? 

It is more than suspected when the young of any domin- 
ant species resembles the adult of another species that the 
first species is higher in the life scale ; young frogs, tadpoles, 
resemble fish, which are lower in the life scale ; young butter- 
flies, caterpillars, resemble worms, which are lower. At any 
rate it will be valuable to obser\-e carefully the plants you 
study at all available ages. Do all the "baby bean" work 
over again from these points of view. 



"Of what use are these prickly hairs that garnish the stem?" 

The next day she showed them to him covered with a 
slight hoar frost which, thanks to them, kept at a distance, 
had not chilled her tender skin. 

' ' Of what use in the fine days will be your warm coat wadded 
with down?" 

The fine days came; she cast off her winter cloak and 
her new branches sprang forth free from this silken envelope, 
henceforward useless. 

"But if the storm rages the wind will bruise thee." 

The wind blew and the young plant, too feeble yet to 
dare to fight, bent to the earth and was defended in yielding. 

Sointine in Picciola. 



PART II. 



CONTENTS OF PART II. 



Page 

Introductory. How to Study a Flower 171 

Inflorescence 172 

The Lily Family 176 

The Rose Family 180 

The Crowfoot Family 182 

The Magnolia Family 183 

The Barberry Family 183 

The Water-lily Family 184 

The Poppy Family 184 

The Mustard Family 185 

The Violet Family ". 186 

The Pink Family 187 

The Purslane Family 187 

The Mallow Family 188 

The Geranium Family 189 

The Pulse Family 189 

The Teasel Family 190 

The Thistle Family 191 

The Nightshade Family 192 

The Sage Family 193 

The Pokeweed Family 194 

The Morning-glory Family 195 

The Nettle Family 197 

The Sycamore Family 198 

The Walnut Family 198 

The Oak Family 200 

The Willow Family , 201 

The Iris Family 202 

The Amaryllis Family 203 

The Grass Family 203 

The Pine Family 205 

The Ferns 206 

The Mosses 207 

A List of Twenty-eight Other Families with One or More 

Common Plants that Belong to Them 208 



How to Study a Flower. 171 

LESSON CII. 

Introductory. How to Study a Flower. 

Begin with a lily or a simple wild flower, as twinleaf , may- 
apple or spring beauty; a lens like Figure 157, which will 
cost fifty cents, or a simple dissecting microscope like 
Figure 158, which may be had of the Bausch and Lomb 
Optical Co., Rochester, New York, for $2.50, and a pair of 
dissecting needles and a sharp knife will greatly help, and 




Fig 157. Fig. 158 1-2. 

for many of the smaller flowers these things will be neces- 
sary. Don't hurry to cut the flower up; pull its sepals 
down without injuring them and see how many there are 
of them, whether they are free from the corolla and separ- 
ate from each other or not, and make notes of every fact 



172 Nature Study. 

you are able to observe about them. It will richly pay if 
you will draw a sepal as accurately as you can. Next 
study the petals the same way and draw one if they are 
alike; if not draw one of each kind. Next study the sta- 
mens the same way; be sure as to whether these are alter- 
nate with the petals or sepals or both if there are twice as 
many; unless you are sure there are twenty or more, count 
them carefully. Do they grow on the calyx or corolla or 
pistil, or receptacle? Draw one. Next study the carpels. 
How many are there? Distinguish ovary, style, if any, and 
stigma. How many are there of each? Cut the ovary 
across and count the cells and the seeds in the cell and learn 
if you can where the seeds are attached to the ovary. 
Note their color, size, shape and number in a cell. Write 
out the number of sepals, petals, stamens and carpels thus, 
3 — 3 — 6 — 3 for the lily. Cut across an entire flower and 
make a ground plan of it thus, Fig. 158 5^ for the lily. What 
sort of stem leaves has the plant? What sort of root-leaves, 
if any? Draw one of every kind and press and preserve 
for study and comparison one of each kind. What pe- 
culiarity of color, odor, hardness, smoothness, etc., has any 
part of the plant ? For example : The violet has a spurred 
petal; it has two petals hairy within; spring-beauty has a 
long, narrow pair of thick leaves; the corolla of narcissus 
has a crown, etc., etc. Compare every flower studied, with 
everyone previously studied. Do not leave off the study 
as soon as you have finished this inventory and found out 
its name. Compare other and younger plants of the same 
kind that have not yet bloomed; compare older ones or 
watch a growing one till it becomes old; gather the seeds 
from it at last and plant them and raise others. It is only 
as the years go on that we can become really acquainted 
with plants. When we have done all that we can by the 
methods of study here pointed out, there is yet the great 
subject of the minute anatomy of plants, and the physiology, 



Inflorescence. 173 

each of which has its special methods and instruments for 
study that we cannot acquire away from a good laboratory. 
The distribution of plants is a matter of great importance, 
which can be begun in any locality. All these studies, if 
pursued with real plants, are interesting and instructive 
all along. Those who know most about plants, best know 
also that they can never know all about them. The}' do 
not, however, wish there was less to be known. 

In the lessons which follow, some of the characteristics 
of a few common and well known plants will be considered 
with reference to their relationships. Gray's Manual 
describes one hundred and twenty-nine orders of flowering 
plants. These are also called families, each being named 
after some characteristic plant it contains; as, for instance, 
Plantaginaceae or plantain family. Plants should some- 
times be studied with the name of the family to which they 
belong well in mind. A family can only be studied through 
the plants which it includes. It does little or no good to 
memorize the characteristics of a plant group in a book. 
These must grow in one's mind as he studies the plants of 
the group in connection with those of other groups. Noth- 
ing is claimed for these lessons unless they are studied in 
the presence of the plants themselves. If they are thus 
faithfully studied they cannot be otherwise than helpful. 
As a preliminary lesson it is necessary for us to consider 
some of the simpler forms of inflorescence. 



LESSON cm. 

The Arrangement of Flowers on the Stem. Inflorescence. 
How Flower Clusters are Related. 

When flowers or fruit are arranged on the stem as we see 
the wild cherry we call the cluster a raceme. Currents are 
so arranged. Tongue-grass has the same kind of inflores- 



174 



Nature Study. 



cence; so have the flowers and fruit of pokeberry; so has 
shepherd's-purse. This arrangement is shown in Figure 
159. It will be as good nature study work as you can do 
to make a list of all the plants that have their flowers 
arranged this way. The raceme has all its flowers on 

I* 




^ 



^^ 
*^ 

f 

Fig. 159. Fig. 160. Fig. 162. Fig. 164. 

separate pedicels of the same length which grow out at 
different places along the flower stalk. When the spring- 
beauties and the lilies-of-the-valley come again, see if they 
have this arrangement. 




Fig. 161. Fig. 163. 

Another common form of inflorescence is called the spike. 
It is shown in Figure 1 60. Look at the figures of the raceme 
and spike and see if you can tell how they are related to 



Inflorescence. 175 

each other. The raceme becomes a spike when its flowers 
become sessile. 

Figure 161 is a corymb; the raceme becomes a corymb 
when its lower pedicels become lengthened so as to bring 
all the flowers to about the same level. Try without 
reading further to look at Figures 159 and 162, and tell 
how the raceme is related to the umbel. A raceme becomes 
an umbel when its pedicels all grow out from the same 
place. There are many plants whose flowers bloom in 
umbels; the parsnip is one, Queen Anne's lace is another, 
pepper-and-salt, our pretty little harbinger-of-spring, is 
another. All these and many more belong to a consider- 
able order of plants called the Umbelliferae. Many of the 
Umbelliferae bear compound umbels like Figure 163. A 
raceme becomes a panicle, Figure 164, when its pedicels 
branch so that each forms a small raceme. The flowers of 
oats form a panicle. When a panicle thickens by becom- 
ing much branched we call it a thyrse. The lilac and 
horse-chestnut are good examples. 

Many flowers grow in heads, Figure 
165. All the large order called com- 
positae which contains the asters, gol- 
den-rods, dandelions, Spanish needles 
and many others grow so. The teasel 
sycamore and clover are other examples. 
See if you can tell from Figures 162 and 
165 how the umbel might become a 
head. If its pedicels shortened till all 
Fig. 165. - tg -fl owers became sessile it would form 

a head. What is the relationship between the raceme and 
head? 

All these forms of inflorescence may be naked, that is, 
they may have no bracts in among the flowers. This is 
true of the shepherd's-purse and many other cruciferous 
flowers. If a spike has bracts in among its crowded flowers 




176 Nature Study. 

and if it hangs down, — is pendulous, — we call it an ament 
or catkin. The staminate flowers of many of our forest 
trees are in aments. 

It is not the purpose of this lesson to multiply defini- 
tions, but to show kinship of flower clusters and the lesson 
is not learned until the student can look at the pictures 
and tell at once how all are related to the raceme and to 
each other; he must also be able to go to his flowers and 
pick out the several kinds. He will not have been long at 
this exercise before he will learn that the several forms 
shade into each other. Gradually the lower pedicels of 
the raceme lengthen until at last a corymb is the result; 
but no one can tell where one leaves off and the other 
begins. He will find in the lilac, the asters, the goldenrods 
and many other flowers, these forms mixed in every way. 
Nature does not always present the sharp lines our figures 
show so clearly. Everywhere her steps are so gradual 
that all careful students now have to think that her sharper 
distinctions have gradually grown up and presented us at 
last with all her varied forms. Try to interpret this: 

A raceme — pedicels becomes a spike. 

A raceme — rachis becomes an umbel. 

A raceme + longer lower petioles becomes a corymb. 

A raceme + branched pedicels become a panicle. 

A raceme — rachis and pedicels become a head. 

Flowers are, as every one knows, often solitary, that is 
just one growing at the end of a stem ; this arrests the growth 
of the stem and is one form of determinate inflorescence. 
When a stem begins to bloom at the botton and continues 
to grow at the top, as the shepherd's-purse or plantain, it 
may bloom on as long as the season lasts; it is indeter- 
minate. 

If, however, a stem begins to bloom at the top and 
blooms downward, or if a flower cluster begins to bloom at 



The Kinship of Plants. ill 

the center and blooms outward, it cannot bloom indefinitely ; 
its blooming in such cases is called determinate. 



LESSON CIV. 
The Lily Family. 

The Liliaceae. 

The Liliaceae. The Kinship of Plants: What it Means to 
Trace Kinship. 

Every one knows the lily; it is famous in all countries 
and all literatures. The trillium, smilax, onion, star-of- 
Bethlehem, grape-hyacinth, lily-of-the-valley. Solomon's- 
seal, asparagus, dog-tooth violet, and other less common 
plants belong to the lily family. Instead of saying calyx 
and corolla, Ave give one name, perianth, to both in the 
lily, because both are generally colored alike. The peri- 
anth consists of six floral leaves. There are generally six 
stamens and a three-celled ovary. Many of the liliaceae 
grow from some sort of underground fleshy part like the 
rootstock of Solomons-seal, see Fig. 55, the bulb of the lily. 
Figure 71, etc. This enables them to bloom early, com- 
pare Lesson LXXXII. It is also true that some of the 
lilies have the blossom already formed underground, so 
that when the warm davs of spring come there is nothing 
to do but push them above ground and unfold them. 

As the season advances, mark the spot where miliums 
and dog-tooth violets grow and dig them up in September 
and even- month thereafter to see the slowly forming 
flower. 

Series I. Seed-Bearing Plants. 

Two series of plants are recognized; those that bear seed 
and those that do not. The lily bears seeds and so belongs 



178 Nature Study. 

to the first series, the Spermatophytes or seed-bearing 
plants. 

Classes. 

There are two classes of seed-bearing plants; those with 
one seed leaf called monocotyledons, and those with two 
called dicotyledons. The lilies belong to the monocotyle- 
dons, that is, they have but one seed-leaf. Every one 
should examine germinating corn and beans at several 
different stages to see the difference between plants with 
one and two seed-leaves. The bean is a dicotyledon. The 
lilies have stems like the smilax, palm and corn, see Lesson 
LXXVI. The leaves are generally parallel veined; com- 
pare the venation of the lily or dog-tooth violet with the 
maple, (palmately veined) and the beech (pinnately 
veined). It is important to notice also that the parts of 
the flower are generally in threes, as in the case of the lily, 
three sepals, three petals, six (two times three) stamens 
and a three-celled ovary. 

Families. 

These monocotyledonous qualities, the lily family shares 
with other monocotyledonous families, as the iris family, 
the amarylis family, the grass family and several others. 
Three lessons following this, Lessons CXXIX, CXXX and 
CXXXI will be about the blue flag, the amaryllis and the 
oats ; and every one should note especially how they differ 
from the lily; this will be a beginning of acquaintanceship 
with family differences. The various families are made up of 
more or fewer groups each of which is called a genus (plural 
genera). The members of each genus are more nearly 
related than they are to the members of other genera; 
among the liliaceae the Solomon's-seal, the dog-tooth violet, 
the lily and the trillium represent four genera. These 
should be carefully compared with each other to get a 



The Kinship of Plants. 179 

notion of differences that are generic. Notice in Solomon's- 
seal that the bracts are not green but membranaceous, 
scarious we call them; that the stamens grow on the peri- 
anth, perigynous, that the perianth is united, cylindrical and 
six-notched at the summit, that the anthers open within, 
(introrse) , and that none of these things are true of the others ; 
they have no bracts, their stamens are hypogynous, i. e., 
they grow on the receptacle or at the base of the distinct 
segments of the perianth; that they open on the back or 
at the side or, in the case of the trillium, sometimes within. 

Genera. 

The Erythronium (dog-tooth violet) is distinguished in 
this group by a scape which comes from a solid bulb and 
bears generally a single flower and a pair of smooth, shining 
leaves that sheathe the scape at the base. 

The lily is borne on a leafy stem from a scaly bulb. Its 
perianth-parts are colored alike and wither. 

The trillium bears three leaves in a whorl, its sepals are 
leaf -like and persistent; it has a solitary flower and its 
leaf-bearing stem comes from a tuber-like rootstock. 

Compare the pistils of these four and any other liliaceous 
genera; compare their seeds. When we have come to look 
unweariedly and exhaustively at things, comparing one 
with another, we shall have one necessary accomplishment 
of the naturalist. 

Species. 

There are two common dog-tooth violets, the yellow and 
the white. These are different species. Find them and 
make out all their differences. Which has leaves with 
few or no spots? Which has spreading stigmas? Which 
has teeth on the inner division of its perianth? These 
differences of color and slight differences of form when they 
reappear with considerable certainty in the descendents of 



180 Nature Study. 

each, constitute specie-distinctions. You will often have 
trouble in distinguishing species. Naturalists, however 
learned they may be, have this trouble. This is because 
species vary. If you seek seriously to know all the plants 
of your neighborhood by name you will quickly learn that 
species change. No one can define species with a definition 
that will always hold. Man is a species ; one does not have 
to look long at a negro, an Indian, a Chinaman, and a 
white man to learn that species greatly vary. We call the 
different sorts varieties when they breed true, have a 
habitat of their own and between their home and the home 
of the species all the differences fade gradually out. There 
are many varieties of Indian corn known to all of us. 

If now we label the yellow dog-tooth violet, it is, first: 
Erythronium americanum, this is its specific name. All 
the millions of individuals, its uncles, cousins and grand- 
fathers, resemble it enough to be mistaken for it. They 
are its near kin. Its generic name is Erythronium. Its 
relatives of this degree are more numerous but less akin, 
have fewer points in common with it. Its order name is 
Liliaceae and of relatives removed so far there is an almost 
uncountable number of individuals but they have yet 
fewer points in common. 

It belongs to the monocotyledons and at this remove, its 
relations again vastly increase, but they are less akin, the 
grasses are now among them. 

The monocotyledons and the dicotyledons belong to the 
Spermatophytes. At this remove, all plants that bear seeds 
are akin to the dog-tooth violet. Finally it is a plant 
instead of an animal and this remove makes the number 
of its relations unthinkably great. It is alive instead of 
dead and this makes the animals more like it than minerals 
are. To classify is to trace out kinship. 

Dog-tooth violet is a living thing, a plant, a spermato- 
phyte, a monocotyledon, a liliaceous plant, an erithronium, 



The Rose Family. 181 

an Erithroniiim americanum. If we know the meaning 
of these words they will all give us information about our 
plant. 

"It is the naturalist rather than nature that draws hard 
and fast lines everywhere and marks out abrupt boundaries 
where she shades off with gradations. 

One of the lessons which -the philosophical naturalist 
learns or has to learn is that differences, the most wide and 
real, in the main, and the most essential, may nevertheless, 
be here and there bridged over by gradations." 

Asa Gray in Darwiniana, page 289. 



LESSON CV. 
The Rose Family. 

The Rosaceae. 

The apple, peach, pear, plum, cherry, wild cherry, 
spiraea, Waldsteinia, strawberry, mountain ash, haw- 
thorn, raspberry and many other common plants as well 
as the rose belong to this family. Find out the character- 
istics of this order by examining the flow T ers instead of 
reading from a book. Get a wild rose for your first lesson. 
How many petals has it? Are they all separate? Do they 
fall off or pull off in one piece or more than one? Do all 
the sepals grow together at the base? Are the stamens 

Note — The order of these lessons has been determined by the 
sequence of Plant Families in Gray's Manual, except in the case of 
the Lily Family and the Rose Family. These I have placed first 
because they are well known, comparatively simple and can be 
had at almost any time of year either cultivated or wild. 

In teaching, the order of these lessons is of so little importance 
that it should be determined solely by the ease of obtaining abund- 
ance of fresh material for studv. 



182 Nature Study. 

few or many? Do the stamens and petals grow on the 
receptacle with the sepals and pistils or do they grow on 
the rim of the calyx tube? Are the pistils few or many? 
If you will answer these questions you will know some 
marked characteristics of the rose, the genus Rosa which 
gives its name to the family. If you memorize the follow- 
ing you will know words only. 

The rosacae are plants with regular flowers; they have 
-five petals and many stamens, all of which grow on the calyx 
tube: that is; they are perigynous. The pistils are one to 
many and except in apples, hawthorns and mountain 
ashes they are distinct. It is important in the study 
of this family that the student become acquainted with the 
receptacle, — the end of the stem on which the flower is 
borne. In spiraea, this is cup shaped, in the strawberry it 
is conical, fleshy and the seeds are imbedded in it; in the 
rose it is urn shaped; open the urn and find the carpels. 
In the apple the parts are differently arranged according 
to the age of the blossom or growing young fruit. The 
perigynous parts become epigynous (on the gynoecium or 
pistil instead of around it) by the growing together of the 
thickened calyx and carpels. In the raspberry the re- 
ceptacle is conical but not fleshy; the fruit comes off and 
leaves it on the stem. In the blackberry it is fleshy and 
comes off with the fruit; is a part of it. 

LESSON CVI. 
The Crowfoot Family. 

The Ranunculaceae . 

The clematis, wind-flower, liverleaf, the meadow-rue, 
the rue-anemone, eighteen species of crowfoot, the marsh- 
marigold, the columbine, yellowroot, larkspur, and other 
less common plants belong to this family. 



The Magnoliao Family. 183 

Any of these flowers will do for a study of the family. 
Several of them should be collected: This will be easy in 
the spring. The sepals, petals {if any), numerous stamens, 
and one to many pistils are all distinct and unconnected; 
This is why your systematic botany describes this family 
first. Nearly all of the family are herbs ; the juice is color- 
less and generally acrid. The marsh-marigold is very 
common; it grows in wet meadows and marshes; often it 
covers several acres. Its gold on its background of green 
is very striking in April and May; its sepals are yellow; it 
has no petals. It is often cultivated as a potted plant. 
Its stamens are numerous and its pistils are about ten; it 
has large, roundish or sometimes kidney-shaped leaves. 

The wind-flower, Anemone nemorosa blooms at about 
the same time. Hunt for it along the edge of the woods. 
It differs from the marsh-marigold in size, color, foliage and 
habitat. The sepals are white, generally tinged with 
purple or sometimes blue, the flower is on a long stalk 
remote from the involucre of compound leaves. 

The liverleaf grows from a rosette of leaves on hairy 
stalks that lived over the winter. It has an involucre of 
simple leaves close to the flower. The flowers of this 
family are easy to study because all the whorls are separate 
and neither sepals, petals, stamens nor pistils are united 
among themselves. Many of them come early in the spring 
and most of them invite to study by their beauty. 

There can be no pleasanter introduction to plants than 
through these flowers. Remember that when only one 
whorl of floral leaves is present we call it a calyx and its 
parts sepals and you cannot go astray. 



184 Nature Study 

LESSON CVII. 
The Magnolia Family. 

The Magnoliaceae. 

The Magnoliaceae are much like the Ranunculaceae in 
their flowers: The pistils, however, cohere and cover the 
receptacle. They are trees instead of herbs. We need to 
learn about this family because our beautiful and valuable 
tulip belongs here. We call it poplar, especially when we 
speak of poplar lumber we mean the lumber of the tulip. 
It is soft, light, durable, easy to work. Our fathers used 
to dig sugar troughs and watering troughs out of it. They 
split it into rails, hued it into timbers for their houses and 
barns and covered their buildings with shingles cut from it. 
Its large, bell-shaped, orange-marked corolla and its green 
leaves, truncated at the end, mark it very distinctly among 
trees. It has three reflexed sepals and six petals. Its 
stamens open outward: Figure 83 shows one of its winged 
seeds hulled out from its united carpels. 

LESSON CVIII. 
The Barberry Family. 

The Berberidaceae. 

We may acquaint ourselves with the Berberidaceae 
through the barberry bush (see Figure 68 for the leaves), 
or the twinleaf , one of our commonest spring flowers. 
The stamens are fewer than in Ranunculaceae, they equal 
the petals in number and are opposite to them. The sepals 
fall off as soon as the flower opens; so one often makes the 
mistake of calling the white petals the calyx. The anthers 
open by lids at the top ; the pod also opens by a lid hinged 



The Mustard Family. 185 

at one side. The flower stalk is low and the flower an inch 
broad. The leaf is divided into half-egg-shaped leaflets. 
The may-apple is an era tic member of this family, with 
stamens twice as many as the petals and not opening by 
lids at the top. It has a peltate leaf and a large fleshy 
berrv. 



LESSON CIX. 
The Water-lily Family. 

The Nymphaeaceae. 

This family is close akin to the foregoing. Even' one 
may have an opportunity to study it in the white water- 
lily which can be had in the markets where it does not 
grow. Consult Lessons XLV and LXXI. 

Find the pistil and see that it is made up of many united 
carpels, that the stamens grow on it, and that the petals 
are in part adherent to it. 

LESSON CX. 
The Poppy Family. 

The Papaveraceae. 

We ought to know something of the Papaveraceae on 
account of the bloodroot. This flower is one of our early 
spring friends. It is solitary, white, has two sepals which 
fall when the flower opens, eight to twelve petals and 
some twenty-four stamens. The pistil is one-celled but is 
made up of two carpels as we learn from the two rows of 
seeds on its wall. It grows from a short rootstock full of 
a red acrid juice. Its leaf is rounded and palmately lobed. 



186 Nature Study. 

LESSON CXI. 
The Mustard Family. 

The Cruciferae. 

This family is a large one; to it belong the mustards, the 
cresses, the radish, cabbage, turnips, peppergrass, shep- 
herd's-purse, sweet-alyssum, and many other plants. 

It is what we call a very natural family, that is it is 
easily distinguished from other families by peculiarities 
that mark its relationships ; when we distinguish plants by 
size, color, leaf -shape, etc., as we often can, we are guided 
by artificial marks as these give little hint of real relation- 
ships. An artificial key seizes on distinctions easily made 
out; a natural key, if one were possible, would guide us to 
the plant by its most significant marks of relationship ; 
a scientific botany bases its distinctions on natural differ- 
ences as much as possible; but because these are often not 
known, and often very difficult of observation, every key 
must be more or less artificial. 

The Cruciferae have four petals arranged in the form of a 
cross: they have six stamens, four long and two short, tetra- 
dynamous, and the pod is a silique, long pod like mustard, 
or silicle, a short pod like that of shepherd' s-purse. These 
pods are two-celled, separated by a thin partition. The 
flowers are so nearly alike that generic characters are taken 
from pods and seeds. An early spring flower, Dentaria 
laciniata, called in Gray toothwort and pepper-root, is a 
good plant on account of the larger flower it bears with 
which to begin an acquaintance with this family; the 
toothwort grows from a rootstock deep in the ground; it 
has a whorl of three much-divided leaves; the flowers are 
white or rose color. 



The Purslane Family. 187 

LESSON CXII. 
The Violet Family. 

Violaceae. 

The violet needs no introduction anywhere. It comes 
early and stays late. Any one who will try, may acquaint 
himself with the parts of a flower through it as there can 
be no doubt about its identity. 

The common blue violet, Viola cucullata, is taken for 
description. The sepals are five slightly united, auriculate, 
green and persistent. The petals are five, one of them 
spurred; the stamens also are five, the anthers grow 
slightly together over the pistil which is made up of three 
carpels. See the open pods at the right in Figure 53. 
The leaves and flower-stalks grow up directly from the 
underground rootstock. The species varies greatly; in 
color from deep violet blue to white; in surface from 
glabrous to villous-pubescent; in leaf-shape from roundish 
heart-shape to kidney-shape or crenate. See description 
of Figure .S3 for its flowers that never open. 

LESSON CXIII. 
The Pink Family. 

The Caryophyllaceae. 

Pinks and carnations we all know and the chickweeds we 
all should know, they grow everywhere in damp grounds ; — 
low plants, about six inches high, with little star-shaped 
flowers. The sepals are four to five; the petals are four to 
five but so deeply two-cleft that they seem to be eight or 
ten. The plant can be told by its deep cleft white petals. 



188 Nature Study. 

The stamens are eight to ten or fewer; the styles are three 
rarely four or five, opposite the sepals; the seed-pod, how- 
ever, is but one-celled; it contains many seeds. The 
leaves are opposite and on the common chickweed they 
have hairy petioles, on the great chickweed they are sessile. 



LESSON CXIV. 
The Purslane Family. 

The Portulacaceae. 

Two of our commonest plants belong to this family, 
purslane and the spring-beauty. We can well learn from 
them what an unsymmetrical flower is. Symmetry refers 
to number. The spring-beauty has two green sepals and 
generally five petals with a stamen on each petal claw. 
The style is three-cleft so we conclude the carpels are three. 
The formula, then is, for the flower, 2, 5, 5, 3 the numbers 
referring in order to sepals, petals, stamens and pistils. 
The flower is therefore unsymmetrical. Stonecrop is 
symmetrical; if you know it you should compare it with 
spring-beauty; it has sepals 4 or 5, petals 4 or 5, stamens 
8 or 10, (twice 4 or 5) and pistils 4 or 5. Compare also a 
flax blossom the formula of which is 5, 5, 5, 5. 

Purslane is a smooth, prostrate, thick-leaved, succulent 
plant, the bane of gardeners. It flourishes in the hottest 
part of July and August. See if its formula is 2, 5 or 6, 7 
to 20, 3 to 8. Compare Lesson LXXII, especially Figure 
117. 



The Pulse Family. 189 

LESSON CXV. 
The Mallow Family. 

Malvaceae. 

Several very common plants belong to this family, the 
holy hock, common mallow, the Hibiscus, the velvet leaf, 
the bladder-ketmia and the Althaea. From some of these 
flowers we should learn what monadelphous stamens are. 
The word means of one brotherhood. A tube rises up from 
the short claws of the petals which bears the stamens. 
We should also learn what valvate in the bud and con- 
volute in the bud mean. Valvate describes the sepals the 
edges of which just meet. Convolute describes the corolla 
the edges of which overlap in such fashion that each petal 
has one edge in and one out. We can also learn well from 
the Althaea, the holyhock and mallow what an involucel 
is. Look for a sort of secondary or exterior calyx 6 to 9- 
cleft around the holyhock and Altheae, of three pieces 
around the mallow. 

LESSON CXVI. 
The Geranium Family. 

Geraniaceae. 

This family contains Oxalis or wood-sorrel, the touch- 
me-not, the Pelargonium, the Geranium or cranesbill and 
the nasturtion, called also the Nasturtium, but this, one 
must not forget is also the generic name of the water- 
cress. 

The Oxalis may be studied as it grows wild almost 
everywhere and it can also be had at the greenhouse ; it is 



190 Nature Study. 

symmetrical with the formula 5, 5, 10, 5. The carpels 
are united into a five-celled ovary. Find out how these 
open; it is unusual. 

The nasturtion offers us a good opportunity to learn 
what an irregular flower is. When the parts of the same 
whorl are unlike we call the flower irregular. This is 
noticeably true of the petals of a pansy or violet; one is 
spurred. See if the sepals of the nasturtion are not unlike ; 
see if the petals are not, and the stamens. Examine also 
the touch-me-not and see that it has a spurred sepal 
larger than the rest. 



LESSON CXVII. 
The Pulse Family. 

The Leguminosae. 

To this family belong the locust and the honey -locust, 
trees, the bean and pea, climbing vines, the redbud, 
a shrub, the Wistaria, a woody twiner, the white and red 
clover, sweet clover and alfalfa, etc., herbs. It will thus 
be seen that size and form have little to do with the make 
up of families. The flowers of this order have usually 
papilionaceous corollas and we should acquaint ourselves 
with this in the pea, bean, locust, redbud, etc. ; they have 
five petals, the lower called the keel, carina, two side ones 
called the wings, alae, and a large enveloping one called 
the banner, vexillum, see Figure. We have seen mona- 
delphous stamens in the Malvaceae; we may now see 
diadelphous stamens in the clover and alfalfa, or better 
still in the locust and pea as the flowers are larger; the 
word diadelphous means in two groups. Generally there 
are nine joined by their filaments in one group and one 
alone or almost separate from the rest. 



The Thistleo Family. 191 

We should also learn well what a legume is as this is the 
peculiarity that gives its name to the family. A legume 
is a one-celled pod, splitting into halves but bearing the 
seeds all on the ventral suture only, in one row. The pea 
and the bean pods are very familiar examples. Consult 
Lesson LXXXVI for a great service rendered the soil by 
the Leguminosae. In North Carolina peas are sown along 
with other crops and they restore the soil for them as clover 
does for us in the North. 



LESSON CXVIII. 
The Teasel Family. 

The Dipsaceae. 

The wild teasel may be seen everywhere along roadsides, 
in pastures and in untilled corners. Its flowers are in a 
dense, large head, conical-elliptical, surrounded by an 
involucre that is loose and longer than the head, but the 
stamens are not syngenesious. The plants are stout, 
coarse, prickly biennials. The fuller's teasel, supposed to 
be derived from this, has the points of its chaffy head, 
hooked, and is used for raising a nap on woolen cloth. 
The chaff of the wild teasel has long, tapering, straight 
points. 

The calyx is coherent but has no pappus. The corolla is 
four-cleft, nearly regular, a fine purple in color. The 
numerous corollas give the head an appearance as pleasing 
as its many daggers will allow. The four stamens grow 
separate on the corolla-tube. 



192 Nature Study. 

LESSON CXIX. 
The Thistle Family. 

The Compo sitae. 

The sunflowers, the asters, the goldenrods, the daisies, 
the burdock, the Spanish needles, the cockle-burs, the 
dog-fennel, the tansy, the ironweed, the yarrow, the ever- 
lastings, the chrysanthemum, the lettuce, the ragweeds and 
many other less known plants belong to this family. The 
dandelion may be found eight months or more of the year; 
hunt in it or the sunflower for these characteristics of the 
family: Flowers in a close head, surrounded by an in- 
volucre of many bracts, which are generally green and with 
stamens united by their anthers, isyngenesious) . If the 
blossom of the dandelion is compared with Figure 72 
a good beginning can be made with this family. It may 
be easily noticed that all the flowers of the dandelion are 
alike. Compare now the sunflower; two kinds will be 
found, the showy outside flowers with a strap-shaped 
corolla and the less showy flowers of the head with tubular 
corollas. Do asters, daisies and thistles resemble the 
dandelion or the sunflower most, in this respect? Much 
profit and pleasure could come from a comparison of all the 
compositae with the dandelion. Examine the involucre 
of the dandelion; is it green? compare it with the involucre 
of the common everlasting; is it green? compare the in- 
volucre of the bur-marigold, (common beggar-tick) gener- 
ally called Spanish needle. Notice that the Spanish needle's 
involucre is very leaf -like, is expanded into a small blade, 
is veined like a small leaf, and helps us to see that the bracts 
of the involucre are reduced leaves. Compare Lesson 
XLIII. 

Compare carefully the pappus on twenty different kinds 



The Mint Family. 193 

of flowers belonging to the compositae; the Spanish needle, 
sunflower and dandelion would be very instructive in this 
respect. The dandelion has a hair-like pappus, Figure 89. 
The Spanish needle's is reduced in number to two or in 
some species to three or four, barbed stickers shown in 
Figure 101. The pappus of the sunflower consists of small 
scales which easily fall off. The chrysanthemum, ox-eye 
daisy, is entirely without pappus, i. e., apetalons. 

Notice that the plaintain -leaved everlasting is dioecious, 
the cocklebur and ragweed are monoecious while the 
dandelion has perfect flowers. We will learn by this 
study how very different in many important respects are 
the flowers that are classed together in this family. 

It is interesting that the prickly lettuce and many other 
compositae have all their flowers ligulate, the everlasting 
and some others have all theirs tubular, while the asters 
and a large number in addition have both ligulate and 
tubular flowers. 



LESSON CXX. 
The Nightshade Family. 

The Solanaceae . 

To this family belong, beside nightshade, the potato, 
the tomato, the tobacco, the ground cherry and the James- 
town weed ("jimson weed") Datura stramonium. Study 
these common plants for the order characteristics; having 
studied all but one see if you can tell by a further study of 
that one why it should belong to the same order. There 
will be real progress in the effort to do this. 

Datura has a green, prismatic, five-toothed calyx, a 
corolla three inches long, white and five-toothed ; there are 
five stamens on the corolla tube and alternate with its 



194 Nature Study. 

lobes. The fruit is a many-seeded capsule armed with 
prickles. Is it two or four-celled at the bottom of the 
capsule? At the top? The jimson is a tall, strong, ill- 
scented annual; smooth, with a green stem, leaves alter- 
nate, sinuate and toothed. The flowers grow in forks 
of the stem on short peduncles. Compare the 
nightshade and potato blossoms with this and each other, 
natt by natt, calyx, corolla, androecium, and gynoecium. 
The importance of doing this can hardly be overstated. 
No teacher and no book can do this for you. 

LESSON CXXI. 
The Mint Family. 

Labiatae. 

Study this family through the everywhere common cat- 
mint or the garden sage or the little gill-over-the-ground. 
Herbs with square stems opposite aromatic leaves, a more 
or less two-lipped corolla, four stamens, two long and 
two short (didynamous) or only two (diandrous) and a 
deeply four-lobed ovary with style rising between the 
smooth or only slightly rough seeds. 

The much-used pennyroyal belongs to this family. 

LESSON CXXII. 
The Pokeweed. 

The Phytolaccaceae . 

The only plant described under this family in Gray's 
Manual is pokeweed. Whatever qualities this plant has 
are, therefore, the qualities of the family. We can learn 
accurately from the fruit or flower what a raceme is. The 



The Morning- Glory Family. 195 

flower has five sepals, no petals, ten stamens, and five car- 
pels united into a pistil of as many cells. The styles are 
ten. The dark purple berries are eagerly eaten by the 
robins and thrushes and should be left, on unused ground, 
for bird food. The succulent stem six to nine feet high 
grows from a large, poisonous root used in medicine. 
Emerson's definition of a weed is "A plant whose virtues 
have not yet been discovered." Pokeweed has at least 
two known virtues and is therefore not a weed. 



LESSON CXXIII. 
The Morning-Glory Family. 

The Convolvulaceae. 

A very common plant cultivated for ornamental purposes, 
the morning-glory, a very useful herb, the sweet potato 
and a very interesting group of twining parasites, the 
dodders, belong to this family. 

The morning-glory has a calyx of five long, narrow, 
imbricated (overlapping) sepals, and a corolla of five united 
petals. The corolla is purple, blue or white and funnel- 
formed. When the parts of the corolla are united, we 
determine of how many parts it is composed by the number 
of its lobes or the number of seams by which it appears to 
have grown together. Try to determine the number of 
parts of several gamopetalous flowers in this way, as, for 
instance, the holyhock, the hibiscus, the pumpkin, the 
watermelon, cucumber, potato, ground-cherry, sage, catnip 
and sunflower and any other gamopetalous flower with 
which you meet. Much practice alone will help you in all 
cases to determine. The gynoecium, (a name for all the 
carpels put together) of the morning-glory is composed of 
three carpels. How can you determine this? Cut across 



196 Nature Study. 

the ovary and count the cells, this is one way. How many 
stigmas are there? This is another way. Is the ovary 
lobed to any degree? How many styles are there? Any 
one of these ways may mislead the beginner sometimes; 
the thing to do is to look at many flowers with care and 
compare your observations with what others have seen. 

The sweet potato rarely blooms when it is raised for 
commercial purposes as it is with us. It furnishes a good 
example of a trailing vine that roots at the joints. See 
how many kinds of support you can find stems adopting; 
as, for instance, upright stems, the oak; right-handed 
twining stems, the morning-glory; left-handed, twining 
stems, the hops; (as one looks down on a twining hop 
it moves with the hands of a watch held face upward; 
as one looks down on a morning-glory it twines against 
the hands of a watch. The hop goes with the sun; the 
morning-glory against it. Does the bean twine like hop 
or morning-glory? The hop is called a sinistrorse climber, 
the morning-glory a dextrorse ;) climbing by tendrils that 
are branches, grapevines; climbing by tendrils that are 
leaflets, the pea; climbing by tendrils that are stipules, 
greenbrier; stems that bend over to the ground for rest, 
the raspberry, etc. The sweet potato is propagated with 
us by means of slips raised in hotbeds. One bushel will 
produce from 3,000 to 5,000 slips (Bailey). 

The dodder Cuscuta arvensis, frequents wet places. I 
have seen it along the flood plains of the Wabash at Peru 
and Terre Haute and I have no doubt it occurs all along 
the stream. It is a small, white, or yellowish- white-stem- 
med, leafless plant that twines about smartweed and other 
river-bottom plants, grows suckers on the side next to the 
host and lives at its expense. It has small whitish scales 
instead of leaves and all its floral organs are pale. The 
calyx has five obtuse lobes ; the corolla lobes are acuminate, 
longer than the tube, inflexed. It has five stamens alter- 



The Nettle Family. 197 

nate with the corolla lobes; the ovary is two-celled, four- 
ovuled. This description is written from Cuscuta arvensis; 
it will vary somewhat with the species of the dodder. 

Notice how small is the stem and how large in proportion 
are the flowers and seed pods. The dodder has met the 
usual fate of the parasite; it gets digested food from its 
host and does not need foliage leaves; it has none; it has 
doubtless lost them from disuse; its pale scales are rudi- 
mentary organs. It has no roots extending to the ground 
for the same reason ; and no stem to support it. It matures 
many seeds as this is its means of survival. It can cling, 
pierce its host and get food and reproduce. It is wholly a 
dependent, a degenerate. It is eminently adapted to its 
kind of life. It is not necessarily on the road to extermina- 
tion but it is barred from the independent, aspiring life of 
the oak or thistle. It has been sentenced for laziness and 
theft to a sort of perdition, not to extinction. Don't seek 
for a permanent thousand-dollar clerkship for yourself or 
for your boy at Washington. 



LESSON CXXIV. 
The Nettle Family. 

The Urticaceae. 

The elms belong to this family. The slippery elm, called 
also the red elm, may be known among elms by its large, 
(four to eight inches) and very rough leaves, its slippery 
inner bark and its nearly sessile flowers. The bark is used 
in medicine. The leaves are oblique, Figure 26, alternate 
and two-ranked as are the leaves of all the elms. The 
American or white elm is somewhat commoner, especially 
in lawns, see Lesson IV, Figure 5. Its leaves are two to 



198 Nature Study. 

four inches. Its buds and branchlets are smooth and its 
branches never corky. Its fruit is winged all round 
notched at the apex and ciliate. Its flowers are on slender 
drooping pedicels. 

There are two other, rarer elms, the cork or rock elm 
and the wahoo or winged, both of which have corky 
branches. The first of these has its leaf -veins nearly twice 
as close together as any other elm; about thirty in the 
cork-elm to seventeen in the American elm and the leaf is 
very smooth. 

The English or field elm is sometimes met with as a shade 
tree; it has very small leaves, about half the size of the 
American elm. 

The elm blossoms are polygamous; that is some are 
sterile and some are fertile and some are perfect. They 
have a four to nine-cleft calyx, four to nine stamens and 
a one to two-celled ovary; the seed is single. 

The hackberry also belongs to this order; it bears a 
globular drupe (fruit with stone within) on a peduncle 
twice as long as the petioles of its leaves and can be told 
among our trees by this and its oblique leaves. Its 
polygamous-monoecious flowers have a five to six-parted 
calyx with five to six stamens and a one-celled ovary. 

The osage orange, so extensively used for hedges, the 
mulberry, the nettle, monoecious or dioecious, the hop 
and the hemp, dioecious, all belong to this family and may 
be studied in comparison with other members of it. 

LESSON CXXV. 
The Plane-Tree Family. 

The Platanaceae. 

Our sycamore is our largest tree; it is common along all 
our streams; it is striking on account of its smooth, white 
bark and its large palmately veined, palmately lobed leaves. 



The Walnut Family. 199 

The petioles of the leaves cover and protect the buds as 
long as the leaves hang on. Its flowers are monoecious, 
in separate, naked heads. Scales are mingled among the 
flowers. The seeds are furnished with a ring of hairs 
about the base. 



LESSON CXXVI. 
The Walnut Family. 

The Juglandaceae. 

This family is made up of the hickories and walnuts. 
Of the walnuts there are two kinds common with us, the 
black walnut, with the unhulled nut round, and the white 
walnut, called also the butternut, with the unhulled nut 
elliptical, hairy, and glutinous; both kinds have alternate, 
pinnately compound leaves. The wood and the bark of the 
butternut are lighter colored than those of the black walnut, 
and, in general, have fewer leaflets on a leaf (five to seven 
pairs) than the black walnut (7 to nine pairs). All the 
trees of this family are monoecious, the sterile flowers 
being in catkins, (aments) and the fertile single or in 
small clusters. The fertile flowers of the walnut have a 
four-toothed calyx which bears four small petals; styles 
and stigmas, two. The sterile have a calyx three to six 
cleft and clinging to a bract, twelve to forty stamens. 

There are two common shellbark hickories, one Carya 
alba, which bears a thin-shelled nut about an inch long 
and has from five to seven leaflets. The other, Carya 
sulcata has a nut one and a half to two inches long with a 
thick shell hard to crack; it has seven to nine leaflets. 
The sterile catkins are generally in threes. The fertile 
flowers have a four-toothed calyx and two to four sessile 



200 Nature Study. 

stigmas. There are also two bitternuts; one, called pig- 
nut, has from five to seven leaflets with the catkins and 
young leaves smooth. The nut is oblong or oval, one and 
a half to two inches long. The other is swamp-hickory 
with nut globular and about an inch long, and having 
seven to eleven leaflets. The catkins and young leaves 
are more or less pubescent. The bark of the bitternut 
does not peel off in strips running up and down the tree as 
it does in the shagbark. The walnuts and shagbarks are 
among our most valuable timber. 



LESSON CXXVII. 
The Oak Family. 

The Cupuliferae. 

The oaks, birches, beeches, the chestnut, the hazelnut, 
the water-beech, the ironwood, and the alders belong to 
the Cupuliferae. The word means cupule-b earing or cup- 
bearing; it refers to the cup in which the acorns or nuts 
grow. This is made up of many small scales in the oak; 
the many scales form a sort of four-lobed involucre in the 
chestnut, and beech. The scale is leaf-like in the water- 
beech, and a closed sack in the ironwood. The flowers are 
monoecious, the sterile in catkins, the fertile, solitary or 
variously clustered. It is quite impossible to get a knowl- 
edge of these small, inconspicuous green or greenish-yellow 
flowers without carefully examining them in the spring. 
The leaves of all this family are pinni-veined, see Figures 
13, 14, 16, 17, 20 and 26. The birch may be known by its 
bark peeling off in horizontal strips, the ironwood by its 
bark shredded longitudinally, the oaks by the fact that 
they bear acorns; the hazelnut is a bush not a tree, and 



The Willow Family. 201 

its nut is inclosed in leaf-like bracts. We should learn 
from this lesson what a cupule is — the cup of an acorn, 
what a pinni -veined leaf is. What a lobed leaf is (white 
and red oaks have them). What a serrate leaf is (the 
chestnut and beech have them). What a chestnut -bur 
is Fig. 104. What monoecious trees are. Lessons 
XVIII and XIX. 

Red oaks, of which we have four, have their lobes awned ; 
Figure 16. White oaks, of which we also have four, have 
their lobes rounded, Figure 14. Chestnut-oak leaves have 
their leaves notched not lobed. Figures 13 and 17. 



LESSON CXXVIII. 
The Willow Family. 

The Salicaceae. 

The willows and poplars belong to this family. The 
white willow can be told by its yellowish twigs, and the 
whitish under side of its somewhat short leaves. It is one 
of the largest willows we have, is often planted on lawns. 

The black willow has foliage of a much darker green, 
and is the common willow along streams. 

The long-leaved willow has the notches, serrations, far 
apart on its long, narrow, whitish leaves. 

The weeping willow no one can mistake on account of 
its drooping branches. 

The "pussy willow" (Salix discolor) can be told by its 
thick aments, oblong-cylindrical, close-sessile, one inch or 
more long, appearing before the leaves in earliest April. 
These aments are the flowers of the willow. The family 
is dioecious, so seeds grow on only a part of the poplars and 
willows. 



202 Nature Study. 

In the "pussy willow" catkins, one flower will be found 
to each bract without a perianth. These bracts are dark 
red or brown becoming black and are clothed in long, 
glossy hairs. 

There are at least fifteen other kinds of willows and some 
of these kinds have been cultivated by gardeners and 
intercrossed until many widely different varieties have 
been produced. That such a thing can be done is very 
interesting; it throws much light on our very many kinds 
of animals and plants. Read Darwin's "Animals and 
Plants Under Domestication." 

The Carolina poplar, cottonwood, is much used as a 
shade tree on account of its beauty and rapid growth; it 
has large, crenate, deltoid, flat-petioled leaves. The 
Lombardy poplar has similar leaves but they are smaller, 
wider than long and the branches grow up almost straight 
close to the tree giving it a spire-shaped appearance by 
which it can be told. 

The white poplar has leaves slightly lobed rather than 
notched, very white-tomentose below; the young twigs 
are white hairy as well. 



LESSON CXXIX. 
The Iris Family. 

The Iridaceae. 

This family, the Iridaceae, is introduced solely on ac- 
count of the blue flag which grows in damp places along 
streams. Notice that its perianth is six-cleft, that it is 
adherent to the ovary, (is it in the lily?) and that it has 
but three stamens, the anthers of which open outward, 
extrorse, one under or outside of each of the three large 



The Grass Family. 203 

expanded petalloid stigmas. Compare Lesson XLVI on 
the leaf-origin of the pistil. Notice the two-ranked, sword- 
shaped, equitant leaves. 

Compare the flower of Iris with Crocus. Learn from 
these what an epigynous flower is, i. e., a flower in which 
the floral organs grow on the pistil. Is the perianth-tube 
of the crocus longer than it is in the iris? Does the crocus 
flower grow sessile on the corm? Are all the leaves of the 
crocus root-leaves? 

LESSOX CXXX. 
The Amaryllis Family. 

The Amaryllidaceae . 

This family is important for us because the narcissus, 
snowdrop, amaryllis and daffodil, common garden flowers, 
belong to it. Figure 45 shows an amaryllis. It resembles 
the iris in having the perianth adherent to the ovary and 
it resembles the lily in having six colored divisions and 
six stamens. The narcissus and daffodils have a crown 
on the throat of the perianth. The daffodil is yellow with 
a large yellow crown. The narcissus is white with a small 
yellow crown. The snowdrop is white and without a 
crown. A main thing we should learn in this lesson is the 
intermediate character of the amaryllis family between 
the lily family and the iris family. 

LESSON CXXXI. 
The Grass Family. 

The Gramineae. 

The Gramineae include the wheat, oats, rye, barley, 
timothy-grass, orchard-grass, blue-grass, foxtail, Indian 
rice, or water oats, and Indian corn and manv other sorts 



204 Nature Study. 

of grasses. A very large and most important order o 
plants as our cereals belong to it and it furnishes the 
chief food of domestic animals. 

A good way to begin the study of this family is with 
oats in the flowering season. 

Find the central stem of the "head," the axis of inflores- 
cence ; its several side branches ; some of these are branched, 
others not. Oats furnishes a good example of a panicle, 
see page 173. See if each final branch or spikelet does not 
bear two or three flowers. At the base of each spikelet 
are two empty glumes. We call them glumes because 
they are not quite opposite and they are a little below the 
flower, otherwise we should call them an involucre. Is the 
spikelet that bears these glumes and the flowers above it 
flat? Find two more glumes for each flower, an outer, 
larger one that encloses the flower and the smaller one on 
the other side of the spikelet called the palet. If these 
two glumes were alike and opposite we should doubtless 
call them sepals ; they are generally called the upper and 
lower palets. Find inside of these the three stamens 
growing distinct on the receptacle (hypogynous) ; the 
pistil is made up of a top-shaped, hairy ovary and two styles 
that are clothed with hair-like stigmas. At the base of 
the upper palet, between its edges, find two very reduced, 
bract-like scales called the lodicules. It is probable that 
these bractlets are all that is left of the perianth of the 
flower of the grasses. If this lesson is faithfully done and 
is followed by a similar lesson with wheat and the cereals 
and then with the larger grasses it will end in the ability 
to become acquainted with the grasses; an acquaintance 
that makes for one many friends for the grasses are found 
everywhere. The Gramineae can be told by their hollow 
stems with closed joints, their alternate two-ranked leaves, 
the sheaths of which are split on the side opposite the blade, 
and their hypogynous, solitary flowers in the axils of two- 



The Pine Family. 205 

ranked glumes. Corn should be studied as an interesting 
variation, having the staminate flowers at the top, and 
man}- pistillate flowers, as many at least as there are 
grains afterward, on a spadix, the cob, and surrounded 
together by the glumes, the husks. 

In many parts the Indian rice may be studied to see an 
instance in which the pistillate flowers are above the 
staminate. This arrangement favors cross-pollination from 
another plant, since pollination is almost sure to occur 
when the wind is blowing. I saw, August 3rd, 1903, 
Indian rice from ten to fifteen feet high at English Lake, 
Indiana. Experiments are being carried forward now 
looking toward its cultivation for economic purposes. 



LESSON CXXXII. 
The Pine Family. 

Coniferae. 

To this family belong the pine, spruce, arborvitae, fir, 
tamarack, (hackmatack or larch) white cedar, hemlock, 
yew, juniper and bald cypress. The leaves of the pine 
are in clusters or bundles of from two to five and are ever- 
green. The larch has its leaves clustered many in a fascicle, 
and they are deciduous. The leaves of the spruce are 
scattered singly over the branch and each has a short 
brown petiole. Compare Lessons VI, VII and XXXIX, 
Figures 7, 8, 9 and 64. The leaves of the hemlock are 
scattered singly and have a green petiole. The leaves of 
the fir are scattered singly, have no petiole but are attached 
to the stem by a disc. Compare Lesson III, Figure 4. 

The arborvitae has its leaves scale-like in four rows on 
the stem; they completely cover the stem; the spray is 



206 Nature Study. 

flat. The common juniper has its awl-shaped leaves in 
whorls of three; the red cedar has its scales awl-shaped 
appressed to the stem, four-ranked, but the spray is 
roundish, not flat like arborvitae. The bald cypress, so 
common on the margins of lakes and rivers and in the 
swamps of Florida and sometimes cultivated in the North 
has its leaves on a flat spray which it sheds together with 
the leaves. As it grows in a few feet of water its roots 
require some means of getting air. This is furnished by 
the spongy knees which grow up from the roots and the 
enlarged base of the trunk which is also porous. 

The family name means cone bearers, in allusion to the 
cones made up of many scales under which the winged 
seeds, Figure 81, grow. 



LESSON CXXXIII 
The Ferns. 

Filices. 

This order comprises the beautiful ferns which grow 
everywhere in damp, shady places. The maiden hair fern 
is the one known, perhaps, to most people. Its frond 
stems are shining black; its botanical name is Adiantum 
pedatum; the specific name pedatum is in allusion to the 
mode of branching of the frond which is supposed to 
resemble a bird's foot. For the general characteristics of 
ferns, see Lesson LX and Figures 94 to 100. 

The spores on the under side of the leaves should be 
sowed on damp soil in a flower pot under a bell glass or 
fruit can and the growth of the fern watched. It should 
be seen that fern fronds grow up from an underground 
stem — a rootstock which also bears roots. Notice that 



The Mosses. 207 

the spores of the maiden hair fern are covered by the 
reflexed margins of the frond. This covering is called the 
indusium. Notice that the fruit dots often grow at the 
end of a comparatively large vein of the frond and that 
the indusium is sometimes attached by a central stem 
(peltate) to the frond; sometimes it is attached all along 
one side. These are items which will help in the classifi- 
cation of the ferns. 



LESSON CXXXIV. 
The Mosses. 

The mosses carpet the damp shaded ground in early 
spring; they also grow on rocks and trees and some of the 
species grow where water trickles over a bank. If this 
water is charged heavily with lime, formations of petrified 
moss in large masses may be formed. Such formations are 
common about Richmond, Indiana. Every one should 
study the mosses enough at least to learn the difference 
between what botanists call the sporophyte (spore bearing 
plant) and the gametophyte (gamete bearing plant). The 
gametes are the two cells, male and female, which unite 
in sexual reproduction. 

In the mosses the sporophyte consists of the long naked 
stem which grows from the summit of the leafy moss plant 
which is the gametophyte. 

Sporophyte and gametophyte are of somewhat equal 
size in the mosses; at least both can easily be seen. The 
connection between them is slight. The dried sporecup 
and its stem can easily be pulled out from the slight de- 
pression it occupies at the top of the leaf -bearing moss, 
the gametophyte. 

In the mosses it is easy to understand the alternation 



208 Nature Study. 

of generations among plants. The microscopic spores 
which are borne in large numbers in the sporecup at the 
top of the sporophyte are scattered by the wind; when 
they alight on damp soil or rocks or bark they begin to 
grow and ultimately they produce not a sporophyte like 
they came from but a gametophyte, a leafy moss some of 
them, in most species male plants, and some of them female. 
These bear, in the rosettes at the top of the stem, each in 
its apporpriate cup, the male and female cells. When 
rain or dew unites the heads of male and female moss 
plants, the male cells swim across and find their way to 
the female cells; one male cell unites with one female cell 
and from the union a sporophyte grows up. In this 
manner are produced in alternation gametophyte, gametes, 
sporophyte, spores, gametophyte, etc. 

Alternation of generations plays an important part in 
both the plant and animal kingdoms ; it cannot be studied 
with any other material to better advantage than it can 
with mosses. Among ferns the gametophyte, Figuie 98, 
is so small that it is usually overlooked. Among our seed- 
bearing plants it is so small it can only be studied with a 
compound microscope. 

There are many other families of plants which cannot 
be noticed even briefly in a work like this. The following 
are a few more that may be studied through the common 
and well known representatives given with each: 

Borraginaceae through Hound's Tongue (sticktight) . 

Anonaceae through Papaw. 

Fumariaceae through Dutchman's Breeches. 

Linaceae through Common Flax. 

Rutaceae through Prickley Ash. 

Vitaceae through Grape. 

Sapindaceae through Buckeye, Maple and Box Elder. 

Anacardiaceae through Sumach. 

Calycanthaceae through Sweet Scented Shrub. 



PlantFamilies. 209 

Saxifragaceae through Hydrangea, Mock Orange, Cur- 
rant and Gooseberry. 

Crassulaceae through Stonecrop. 

Hamamelideae through Sweet Gum. 

Onagraceae through Primrose. 

Cucurbitaceae through Gourd, Pumpkin, Squash, Musk- 
melon, Watermelon and Cucumber. 

Umbelliferae through Harbinger-of-Spring (Pepper-and- 
Salt), Wild Parsnip, Carrot, etc. 

Cornaceae through Dogwood and Sour Gum. 

Caprifoliaceae through Honeysuckle, Elder, Black Haw 
and Weigela. 

Rubiaceae through Galium (Bed Straw, Goose Grass). 

Ebenaceae through Persimmon. 

Asclepiadaceae through Milkweed. 

Polemoniaceae through Phlox and Valerian. 

Scrofulariaceae through Mullein, Butter and Eggs, Snap 
Dragon and Speedwell. 

Bignoniaceae through Catalpa. 

Plantaginaceae through Plantain. Consult Lesson XXI. 

Polygonaceae through Dock, Knotweed and Buckwheat. 

Lauraceae through Sassafras. 

Commelinaceae through Spiderwort. 

Araceae through Indian Turnip, Skunk Cabbage and 
Calamus. 



GLOSSARY 



Adherent, applied to the calyx, etc., when growing fast to the ovary. 

Alae, Side petals of a papilionaceous flower. 

Anient, 173. A pendulous spike. 

Androecium, the stamens taken together. 

Anther, Pollen-container at top of filament. 

Apetalous, without petals. 

Auriculate, with ear -shaped appendages. 

Bract, a reduced leaf, 66. 

Bulb, a fleshy scaled underground leaf bud, 73. 

Calyx, the outside whorl of a flower. 

Carina, the lower united petals of a papilionaceous flower. 

Carpel, "a simple pistil or one part of a compound pistil." 

Catkin, Same as ament, 173, apendulous spike. 

Cleistogamous, a term applied to flowers that do not open. 

Complete, applied to a flower containing the four whorls. 

Convolute, overlaping with one edge in and one out. 

Corm, the solid enlarged fleshy base of a stem. 

Corolla, the second whorl of floral leaves. 

Corymb, 173. 

Determinate, applied to flower clusters blooming first at the center 

or top. 
Diadelphous, applied to stamens united into two sets by their 

filaments. 
Diandrous, Having two stamens. 
Dicotyledonous, Having two seed-leaves. 
Epigynous, on the pistil. 

Equitant, applied to enfolding upright leaves like those of blue flag. 
Extrorse, opening outward. 
Feather-veined, veined like a beech leaf. Same as pinni-veined, 

200. 
Filament, the support of the anther in a stamen. 
Free, said of the flower whorls when they are separate. 
Gamete, 207 , 160. 
Gametophyte, 207 . 
Gamapetalous, petals united. 
Glumes, the chaffy bracts of the grasses. 
Gynoecium, the carpels taken together. 
Head, 173. 



Glossary. 211 

Hypogynous, tinder the gynoecium. Said of parts growing on the 

receptacle. 
Imperfect, said of a flower lacking stamens or pistils. 
Incomplete, said of flowers lacking some whorl. 
Indusium, the covering of sori in ferns. Figs. 95, 96, 100. 
Inflorescence, flower arrangement on the stem. 
Introrse, opening inward. 
Involucel, a secondary involucre. 
Involucre, a whorl or whorls of bracts around a flower or flower 

cluster. 
Irregular, Having the parts of the same whorl unlike, 189. 
Legume, the fruit of the Leguminosae — a bean, 189. 
Ligulate, Strap shaped. Like the corolla of dandelion. 
Lodicules, 204. 

Monocotyledonous, with one cotyledon. 
M onadelphous , united by filaments into one group, 188. 
Ovary, the seed bearing, lower part of the carpel. 
Pales, the thin, upper, hyaline chaff of the grasses. 
Palmately Veined, veined like a sugar -maple. Fig. 22. 
Panicle, 173. 

Papillionaceous, said of a corolla like the bean and pea have 
Parallel Veined, veined like corn. Fig. 27. 
Peduncle, a flower stalk. 
Peltate, umbrella shaped. 

Perfect, said of a flower having stamens and pistils. 
Perianth, a term for both calyx and corolla. 
Perigynous, around the gynoecium; said of petals and stamens 

when they grow on the calyx. 
Persistent, not falling off. 
Petal, one of the parts of the corolla. 
Petiole, the stem of a leaf. 

Pinnately, veined like the elm, Fig. 26, or compound like Fig. 25. 
Pistil, "the seed-bearing organ of the flower." 
Polygamous, bearing pertect, fertile and sterile flowers. 
Polypetalous, having more than one petal. 
Raceme, 173. 
Rootstock, 206, Fig. 53. 
Sepal, one of the parts of the calyx. 
Sessile, without a stem. 

Silicle, a short pod like shepherd's purse has. 
Silique,- a long pod like mustard has. 
Sori, the fruit dots on underside of fern leaves, 89, 90. 



212 Nature Study. 

Spermatophyte, a seed-bearing plant. 

Spike, 173. 

Spiketet, 204. 

Sporangium, a spore cup. Figs. 97, 105. 

Spores, 207, 89, 96. 

Sporophyte, 207. 

Stamen, one part of the androecium. 

Stigma, the topmost, naked part of the pistil. 

Style, it connects the stigma and ovary. 

Symmetrical, said of a flower with same number of parts in each 

whorl. 
Syngenicious , applied to stamens united by their anthers, 191. 
Thyrse, a thick much compounded panicle, 173. 
Unsymmetrical, said of a flower with differing numbers in its whorls. 
Valvate, edges meeting. 
Vexillum, the large uppermost petal of the leguminosae, as the 

bean. 



INDEX. 



Abutilon, 24, 25,* 26. 

Agave, 109. 

Alga, 43. 

Alternation of Generations, 
207. 

Amaryllis, 38, 39, 203. 

Anient, 173. 

Anemophilous Plants, 48. 

Animals and Plants, 148. 

Annual Herbs, 50. 

Antheridium of Moss, 159, 160. 

Anthrax, 142. 

Ants, 44. 

Apple, 9, 13, 28, 75. 

Archegonium of Liverwort, 
160. 

Asexual Reproduction, 152. 

Aspen, 16. 

Bacteria, 141. 

Balm of Gilead, 16. 

Bark, 122, 125, 128. 

Bean, 40, 79. 

Beech, Leaf -Arrangement of, 
27, 28. 

Beech Leaf, Petiole of, 27. 

Beech Tree, 1, 2, 13. 

Berberidaceae, 183. 

Biennial Herbs, 51. 

Birch, 22, 28. 

Bracts, 66. 

Branches, Horizontal, 12, 13. 

Branches, Vertical, 12, 13. 

Branching, Deliquescent, 8. 

Branching, Excurrent, 6, 7. 

Branchlets, Pendant, 11, 60. 

Broom-Corn, 35. 

Bryant, Wm. Cullen, Quota- 
tion from, 127. 

Buds, 57, 58. 

Bud Scales, 58, 71. 

Bulb Scales, 72, 73. 

Burns, Robert, Quotation 
from, 89. 

Burdock-Bur, 92. 



Butterflies, 41. 

Cane, 35. 

Caryophyllaceae, 187. 

Catkin, 173. 

Cedar, 9. 

Cell, The 151. 

Cherry Tree, The Wild, 3, 9. 

Chestnut-Bur, The, 92. 

Chestnut Leaf, The, 18. 

Chlorophyll, 146. 

Cleistogamy, 45. 

Climate, 49-62. 

Clover, 26, 132. 

Cockle-Bur, 92. 

Compass-Plant, 16. 

Compositae, 191. 

Complete Flower, 32. 

Coniferae, 205. 

Convolvulaceae, 194. 

Corn, 34, 116. 

Corn and Soil, 22, 23, 

Corymb, 173. 

Creeper, Virginia, 14. 

Cross-Pollination, Experiments 

in, 46. 
Crowfoot Family, 182. 
Crow-Roost, 94. 
Cruciferae, 185. 
Cupuliferae, 200. 
Currents of Water, 93. 
Cut-Leaved Maple Leaf, 17. 
Dandelion, Pappus of, 74, 84, 

86. 
Datura, 137. 

Deciduous Forests, 4, 54. 
Desert Plant, 109 
Diatoms, 104, 105. 
Dioecious Species, 36. 
Dispersal of Seeds, 82-100. 
Elm Tree, The, 8, 13. 
Elm Leaf, 19. 
Entomophilous Plants, 47. 
Epilobium, 38. 
Erigenia Bulbosa, 158. 



*When the paging is given in this type an illustration will be found. 



214 



Index 



Evergreen Leaves, 55, 56, 57. 

Excurrent Branching, 6. 

Felices, 206. 

Fern, 89, 90, 121, 206. 

Fern, 89, 90, 121. 

Fern Leaf, Section of, 54. 

Fibro-Vascular Bundle of Smi- 
lax, 114, 115. 

Fibro-Vascular Bundle of Corn, 
116. 

Fibro-Vascular Bundle of Ger- 
anium, 117,118. 

Fibro-Vascular Bundle of Fern, 
121. 

Fire- Weed, 38. 

Fir-Tree, The, 6, 7. 

Food, 135. 

Forestry, 113. 

Fruit and Seed-Dispersal, 94. 

Fuel, 137. 

Genera, 178. 

Geranium, The Cross-Section 
of a Stem of, 117, 189. 

Ginkgo Leaf, 19. 

Goethe, 40, 152. 

Gramineae, 203. 

Grass Family, 203. 

Greenbrier Leaf, 19. 

Growth, 164. 

Hazelnut, 13. 

Head, 174. 

Heart-Wood, 122, 124. 

Hedge, 13. 

Horse-Chestnut Leaf, 18. 

Hyacinth, Water, 153. 

Hydrophytes, 101. 

Inflorescence, 172 

Infusorial, Earth, 105. 

Insects and Pollination, 40, 41. 

Indaceae, 202. 

Juglandaceae, 198. 

Katahdin, Mt., Birches Grow- 
ing on, 22. 

Koch, Robert, 142. 

Labratae, 193. 

Land Plants, 111. 

Larch, European, 11. 

Leaf, The, 62-77. 

Leaf -Arrangement, 28. 

Leaf, Cross-Section of, 76. 

Leaf, Foliage, 62. 

Leaves, Compound, 18, 19. 



Leaves, Evergreen, 55. 
Leaves, Effect of Shadow on, 

19. 
Leaves, Shapes of, 17, 18, 19. 
Leguminosae, 189 
Lenses, 170. 
Lettuce, Prickley, 16. 
Lichen, 43. 
Light, 1-31. 
Lilac Leaf, 19. 
Lily, 73. 

Linden Seed, 82. 
Live Oak, 61, 62. 
Lumber, 137. 
Magnoliaceae, 183. 
Malvaceae, 188. 
Maple Spray, 15. 
Measuring a Tree, 5, 6. 
Medullary Rays, 119, 120, 123, 

140. 
Microscopic Plants, 104. 
Mint Familv, 193. 
Mistletoe, 140. 
Mountain-Ash Leaf, 18. 
Monecious Species, 33, 35. 
Morning-Glory, 14, 194. 
Morphology of the Laef, 62-77. 
Mosses, 207. 
Moths, 41. 
Mulberry, 36. 
Mullein, 20, 21, 52. 
Mushrooms, 144, 145. 
Mustard Family, 185. 
Nettle Family, 197. 
Night Shade Family, 193. 
North Indiana Field, 101, 103 
Norway Spruce, 11 12. 60. 
Nostoc, 154. 
Nuts, 95. 
Oak Family, 200. 
Oak Leaves, 17. 
Oedogonium, 158. 
Onion, 23. 
Orchid, 41, 42. 
Oxalis, 26. 
Palm, 30, 31. 
Palmetto Brushes, 116. 
Pampas-Grass, 99. 
Panicle, 173. 
Papaveraceae, 184. 
Pappus, 74, 84, 86, 87. 
Parasitic Plants, 140. 



Index. 



215 



Pasteur, 143. 

Pea, Garden, 77. 

Pea, Sweet, 78. 

Perennial Herbs, 53. 

Persimmon Tree, 59. 

Petals, 67. 

Petiole, Behavior of , 13, 14, 15. 

Phylolaccaceae, 194. 

Pilobolus, 97. 

Pine, 10, 19, 29, 205. 

Pine Leaf, Section of, 56. 

Pine, Pitch, 9, 10. 

Pink Family, 205. 

Pistils, 70. 

Pistillate Flowers, 33. 

Plankton, 104. 

Plant Societies, 101, 102-113. 

Plantain, 37, 198. 

Poke-weed Family, 194. 

Pollen, 32, 33, 34. 

Pollination, 32-48. 

Poplar, Carolina, 16. 

Poplar, Lombardy, 14, 16. 

Portulaccaceae, 187. 

Protandry, 38. ' 

Protogyny, 37. 

Protoplasm, 151. 

Pulse Family, 189. 

Pumpkin Vine, 14. 

Purslane, 110, 111, 187. 

Quarter-Sawed Oak, 123. 

Raceme, 173. 

Ragweed, 93. 

Ranunculaceae, 182. 

Red-pak Leaf, 17. 

Respiration of Plants, 150. 

Rings of Growth, 120, 122. 

Rose Leaf, 19. 

Rose Family, 180. 

Rosette Leaf Arrangement, 20 o 

21. 
Root, 130, 131. 
Salicaceae, 201. 
Saprophytes, 144, 145. 
Sap-wood, 122. 
Scott, Sir Walter, Quotation 

from, 16. 
Seeds and Spores, Size of, 89. 
Seed Dispersal, 82-100. 
Seeds that Cling, 91, 92, 93. 
Sepals, 67. 
Sexual Reproduction, 156, 157. 



Shapes of Leaves, 17, 18, 19. 
Sleep of Plants, 24, 25, 26. 
Smartweed Embryo, 162. 
Smilax, 114. 

Soil, Influence of, 22, 23. 
Solanaceae, 193. 
Solomon's-Seal. 53. 
Southey, Robert, Quotation 

from, 65. 
Spanish Needle, 91, 92. 
Species, 178. 
Sperms of Moss, 160. 
Spike, 173. 
Spines, 65. 
Spirogyra, 147, 157. 
Sporangium of Fern, 96. 
Spore Dispersal, 97. 
Spores and Seeds, 89. 
Spring Flowers, 127. 
Spruce, Norway, 11, 12, 13, 60, 
Stamens, 69. 
Staminate Flowers, 33. 
Starch, 134. 
Stem, Influence of Climate 

and Soil on, 22, 23. 
Stem, Main Duty of, 21. 
Stems, 114-129. 
Stomata, 54, 56, 107. 
Storms, 49. 
Streptococcus, 155. 
Struggle for Existence, 80. 
Sweet Pea, 78. 
Sycamore, 19. 
Sycamore-Maple Leaf, 18. 
Symboisis, 42,^43, 95. 
Table of Seed|Dispersal, 100. 
Tamarack, 11, 29. 
Teasel Family, 190. 
Tendrils, 77-79. 
Thistle, 88, 191. 
Transpiration, 64. 
Tumble Weed, 98. 
Twinleaf Embryo, 163. 
Twining Plants, 79. 
Umbel, 173. 
Urbccaceae, 197. 
Uses of Plants, 134-139. 
Vetch, 133. 
Violet Family, 186. 
Walnut, 98, 198. 
Walnut Tree, 3, 4, 5. 
Water, Currents of, 93. 



216 



Index. 



Water Hyacinth, 153. 
Water-Lily, White, 105, 106, 

184. 
Water Plants, 101. 
Willow Family, 201. 
Wind, Influence of, on Plants, 

60, 61, 62. 
Winged Seeds, 82, 83. 



Whittier, John Greenleaf, The 

Palm, 138. 
Xerophytes, 109. 
Yeast, 155. 
Yellow Chestnut Oak, Leaf of, 

17. 
Young Plants, 166. 



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